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authorAndreas Hansson <andreas.hansson@arm.com>2016-03-17 09:51:18 -0400
committerAndreas Hansson <andreas.hansson@arm.com>2016-03-17 09:51:18 -0400
commit041ea8107e4250a9c120a6fde11f3dc415c2fe6a (patch)
tree13c75f78d88ab7c9077babd5e9b8a3a36fcba3d7 /src/mem
parentf5d1dd75e57d9c63c5f6ab4d0c7c0c45f8726a95 (diff)
downloadgem5-041ea8107e4250a9c120a6fde11f3dc415c2fe6a.tar.xz
mem: Create a separate class for the cache write buffer
This patch breaks out the cache write buffer into a separate class, without affecting any stats. The goal of the patch is to avoid encumbering the much-simpler write queue with the complex MSHR handling. In a follow on patch this simplification allows us to implement write combining. The WriteQueue gets its own class, but shares a common ancestor, the generic Queue, with the MSHRQueue.
Diffstat (limited to 'src/mem')
-rw-r--r--src/mem/cache/SConscript2
-rw-r--r--src/mem/cache/base.cc5
-rw-r--r--src/mem/cache/base.hh90
-rw-r--r--src/mem/cache/cache.cc383
-rw-r--r--src/mem/cache/cache.hh76
-rw-r--r--src/mem/cache/mshr.cc27
-rw-r--r--src/mem/cache/mshr.hh63
-rw-r--r--src/mem/cache/mshr_queue.cc146
-rw-r--r--src/mem/cache/mshr_queue.hh115
-rw-r--r--src/mem/cache/queue.hh251
-rw-r--r--src/mem/cache/queue_entry.hh109
-rw-r--r--src/mem/cache/write_queue.cc91
-rw-r--r--src/mem/cache/write_queue.hh97
-rw-r--r--src/mem/cache/write_queue_entry.cc185
-rw-r--r--src/mem/cache/write_queue_entry.hh194
15 files changed, 1285 insertions, 549 deletions
diff --git a/src/mem/cache/SConscript b/src/mem/cache/SConscript
index 01f099f1b..1c9b0027c 100644
--- a/src/mem/cache/SConscript
+++ b/src/mem/cache/SConscript
@@ -37,6 +37,8 @@ Source('cache.cc')
Source('blk.cc')
Source('mshr.cc')
Source('mshr_queue.cc')
+Source('write_queue.cc')
+Source('write_queue_entry.cc')
DebugFlag('Cache')
DebugFlag('CachePort')
diff --git a/src/mem/cache/base.cc b/src/mem/cache/base.cc
index a3ceaafa3..1cbfe713b 100644
--- a/src/mem/cache/base.cc
+++ b/src/mem/cache/base.cc
@@ -68,9 +68,8 @@ BaseCache::CacheSlavePort::CacheSlavePort(const std::string &_name,
BaseCache::BaseCache(const BaseCacheParams *p, unsigned blk_size)
: MemObject(p),
cpuSidePort(nullptr), memSidePort(nullptr),
- mshrQueue("MSHRs", p->mshrs, 4, p->demand_mshr_reserve, MSHRQueue_MSHRs),
- writeBuffer("write buffer", p->write_buffers, p->mshrs+1000, 0,
- MSHRQueue_WriteBuffer),
+ mshrQueue("MSHRs", p->mshrs, 4, p->demand_mshr_reserve),
+ writeBuffer("write buffer", p->write_buffers, p->mshrs+1000),
blkSize(blk_size),
lookupLatency(p->hit_latency),
forwardLatency(p->hit_latency),
diff --git a/src/mem/cache/base.hh b/src/mem/cache/base.hh
index 1f1f1469f..cd21bce91 100644
--- a/src/mem/cache/base.hh
+++ b/src/mem/cache/base.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012-2013, 2015 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -62,6 +62,7 @@
#include "debug/Cache.hh"
#include "debug/CachePort.hh"
#include "mem/cache/mshr_queue.hh"
+#include "mem/cache/write_queue.hh"
#include "mem/mem_object.hh"
#include "mem/packet.hh"
#include "mem/qport.hh"
@@ -72,12 +73,12 @@
#include "sim/sim_exit.hh"
#include "sim/system.hh"
-class MSHR;
/**
* A basic cache interface. Implements some common functions for speed.
*/
class BaseCache : public MemObject
{
+ protected:
/**
* Indexes to enumerate the MSHR queues.
*/
@@ -190,47 +191,29 @@ class BaseCache : public MemObject
MSHRQueue mshrQueue;
/** Write/writeback buffer */
- MSHRQueue writeBuffer;
+ WriteQueue writeBuffer;
/**
- * Allocate a buffer, passing the time indicating when schedule an
- * event to the queued port to go and ask the MSHR and write queue
- * if they have packets to send.
- *
- * allocateBufferInternal() function is called in:
- * - MSHR allocateWriteBuffer (unchached write forwarded to WriteBuffer);
- * - MSHR allocateMissBuffer (miss in MSHR queue);
+ * Mark a request as in service (sent downstream in the memory
+ * system), effectively making this MSHR the ordering point.
*/
- MSHR *allocateBufferInternal(MSHRQueue *mq, Addr addr, int size,
- PacketPtr pkt, Tick time,
- bool sched_send)
+ void markInService(MSHR *mshr, bool pending_modified_resp)
{
- // check that the address is block aligned since we rely on
- // this in a number of places when checking for matches and
- // overlap
- assert(addr == blockAlign(addr));
-
- MSHR *mshr = mq->allocate(addr, size, pkt, time, order++,
- allocOnFill(pkt->cmd));
+ bool wasFull = mshrQueue.isFull();
+ mshrQueue.markInService(mshr, pending_modified_resp);
- if (mq->isFull()) {
- setBlocked((BlockedCause)mq->index);
+ if (wasFull && !mshrQueue.isFull()) {
+ clearBlocked(Blocked_NoMSHRs);
}
-
- if (sched_send)
- // schedule the send
- schedMemSideSendEvent(time);
-
- return mshr;
}
- void markInServiceInternal(MSHR *mshr, bool pending_modified_resp)
+ void markInService(WriteQueueEntry *entry)
{
- MSHRQueue *mq = mshr->queue;
- bool wasFull = mq->isFull();
- mq->markInService(mshr, pending_modified_resp);
- if (wasFull && !mq->isFull()) {
- clearBlocked((BlockedCause)mq->index);
+ bool wasFull = writeBuffer.isFull();
+ writeBuffer.markInService(entry);
+
+ if (wasFull && !writeBuffer.isFull()) {
+ clearBlocked(Blocked_NoWBBuffers);
}
}
@@ -511,19 +494,44 @@ class BaseCache : public MemObject
MSHR *allocateMissBuffer(PacketPtr pkt, Tick time, bool sched_send = true)
{
- return allocateBufferInternal(&mshrQueue,
- blockAlign(pkt->getAddr()), blkSize,
- pkt, time, sched_send);
+ MSHR *mshr = mshrQueue.allocate(blockAlign(pkt->getAddr()), blkSize,
+ pkt, time, order++,
+ allocOnFill(pkt->cmd));
+
+ if (mshrQueue.isFull()) {
+ setBlocked((BlockedCause)MSHRQueue_MSHRs);
+ }
+
+ if (sched_send) {
+ // schedule the send
+ schedMemSideSendEvent(time);
+ }
+
+ return mshr;
}
- MSHR *allocateWriteBuffer(PacketPtr pkt, Tick time)
+ void allocateWriteBuffer(PacketPtr pkt, Tick time)
{
// should only see writes or clean evicts here
assert(pkt->isWrite() || pkt->cmd == MemCmd::CleanEvict);
- return allocateBufferInternal(&writeBuffer,
- blockAlign(pkt->getAddr()), blkSize,
- pkt, time, true);
+ Addr blk_addr = blockAlign(pkt->getAddr());
+
+ WriteQueueEntry *wq_entry =
+ writeBuffer.findMatch(blk_addr, pkt->isSecure());
+ if (wq_entry && !wq_entry->inService) {
+ DPRINTF(Cache, "Potential to merge writeback %s to %#llx",
+ pkt->cmdString(), pkt->getAddr());
+ }
+
+ writeBuffer.allocate(blk_addr, blkSize, pkt, time, order++);
+
+ if (writeBuffer.isFull()) {
+ setBlocked((BlockedCause)MSHRQueue_WriteBuffer);
+ }
+
+ // schedule the send
+ schedMemSideSendEvent(time);
}
/**
diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc
index 724ccc7d6..267497aca 100644
--- a/src/mem/cache/cache.cc
+++ b/src/mem/cache/cache.cc
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2010-2015 ARM Limited
+ * Copyright (c) 2010-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -286,20 +286,6 @@ Cache::satisfyCpuSideRequest(PacketPtr pkt, CacheBlk *blk,
}
}
-
-/////////////////////////////////////////////////////
-//
-// MSHR helper functions
-//
-/////////////////////////////////////////////////////
-
-
-void
-Cache::markInService(MSHR *mshr, bool pending_modified_resp)
-{
- markInServiceInternal(mshr, pending_modified_resp);
-}
-
/////////////////////////////////////////////////////
//
// Access path: requests coming in from the CPU side
@@ -363,11 +349,9 @@ Cache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
// generating CleanEvict and Writeback or simply CleanEvict and
// CleanEvict almost simultaneously will be caught by snoops sent out
// by crossbar.
- std::vector<MSHR *> outgoing;
- if (writeBuffer.findMatches(pkt->getAddr(), pkt->isSecure(),
- outgoing)) {
- assert(outgoing.size() == 1);
- MSHR *wb_entry = outgoing[0];
+ WriteQueueEntry *wb_entry = writeBuffer.findMatch(pkt->getAddr(),
+ pkt->isSecure());
+ if (wb_entry) {
assert(wb_entry->getNumTargets() == 1);
PacketPtr wbPkt = wb_entry->getTarget()->pkt;
assert(wbPkt->isWriteback());
@@ -388,7 +372,7 @@ Cache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
// Dirty writeback from above trumps our clean
// writeback... discard here
// Note: markInService will remove entry from writeback buffer.
- markInService(wb_entry, false);
+ markInService(wb_entry);
delete wbPkt;
}
}
@@ -1239,6 +1223,50 @@ Cache::functionalAccess(PacketPtr pkt, bool fromCpuSide)
void
+Cache::handleUncacheableWriteResp(PacketPtr pkt)
+{
+ WriteQueueEntry *wq_entry =
+ dynamic_cast<WriteQueueEntry*>(pkt->senderState);
+ assert(wq_entry);
+
+ WriteQueueEntry::Target *target = wq_entry->getTarget();
+ Packet *tgt_pkt = target->pkt;
+
+ // we send out invalidation reqs and get invalidation
+ // responses for write-line requests
+ assert(tgt_pkt->cmd != MemCmd::WriteLineReq);
+
+ int stats_cmd_idx = tgt_pkt->cmdToIndex();
+ Tick miss_latency = curTick() - target->recvTime;
+ assert(pkt->req->masterId() < system->maxMasters());
+ mshr_uncacheable_lat[stats_cmd_idx][pkt->req->masterId()] +=
+ miss_latency;
+
+ tgt_pkt->makeTimingResponse();
+ // if this packet is an error copy that to the new packet
+ if (pkt->isError())
+ tgt_pkt->copyError(pkt);
+ // Reset the bus additional time as it is now accounted for
+ tgt_pkt->headerDelay = tgt_pkt->payloadDelay = 0;
+ Tick completion_time = clockEdge(responseLatency) +
+ pkt->headerDelay + pkt->payloadDelay;
+
+ cpuSidePort->schedTimingResp(tgt_pkt, completion_time, true);
+
+ wq_entry->popTarget();
+ assert(!wq_entry->hasTargets());
+
+ bool wasFull = writeBuffer.isFull();
+ writeBuffer.deallocate(wq_entry);
+
+ if (wasFull && !writeBuffer.isFull()) {
+ clearBlocked(Blocked_NoWBBuffers);
+ }
+
+ delete pkt;
+}
+
+void
Cache::recvTimingResp(PacketPtr pkt)
{
assert(pkt->isResponse());
@@ -1248,11 +1276,8 @@ Cache::recvTimingResp(PacketPtr pkt)
panic_if(pkt->headerDelay != 0 && pkt->cmd != MemCmd::HardPFResp,
"%s saw a non-zero packet delay\n", name());
- MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
bool is_error = pkt->isError();
- assert(mshr);
-
if (is_error) {
DPRINTF(Cache, "Cache received packet with error for addr %#llx (%s), "
"cmd: %s\n", pkt->getAddr(), pkt->isSecure() ? "s" : "ns",
@@ -1263,8 +1288,18 @@ Cache::recvTimingResp(PacketPtr pkt)
pkt->cmdString(), pkt->getAddr(), pkt->getSize(),
pkt->isSecure() ? "s" : "ns");
- MSHRQueue *mq = mshr->queue;
- bool wasFull = mq->isFull();
+ // if this is a write, we should be looking at an uncacheable
+ // write
+ if (pkt->isWrite()) {
+ assert(pkt->req->isUncacheable());
+ handleUncacheableWriteResp(pkt);
+ return;
+ }
+
+ // we have dealt with any (uncacheable) writes above, from here on
+ // we know we are dealing with an MSHR due to a miss or a prefetch
+ MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
+ assert(mshr);
if (mshr == noTargetMSHR) {
// we always clear at least one target
@@ -1276,14 +1311,6 @@ Cache::recvTimingResp(PacketPtr pkt)
MSHR::Target *initial_tgt = mshr->getTarget();
int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
Tick miss_latency = curTick() - initial_tgt->recvTime;
- PacketList writebacks;
- // We need forward_time here because we have a call of
- // allocateWriteBuffer() that need this parameter to specify the
- // time to request the bus. In this case we use forward latency
- // because there is a writeback. We pay also here for headerDelay
- // that is charged of bus latencies if the packet comes from the
- // bus.
- Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
if (pkt->req->isUncacheable()) {
assert(pkt->req->masterId() < system->maxMasters());
@@ -1295,6 +1322,12 @@ Cache::recvTimingResp(PacketPtr pkt)
miss_latency;
}
+ bool wasFull = mshrQueue.isFull();
+
+ PacketList writebacks;
+
+ Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
+
// upgrade deferred targets if the response has no sharers, and is
// thus passing writable
if (!pkt->hasSharers()) {
@@ -1470,18 +1503,17 @@ Cache::recvTimingResp(PacketPtr pkt)
if (blk) {
blk->status &= ~BlkReadable;
}
- mq = mshr->queue;
- mq->markPending(mshr);
+ mshrQueue.markPending(mshr);
schedMemSideSendEvent(clockEdge() + pkt->payloadDelay);
} else {
- mq->deallocate(mshr);
- if (wasFull && !mq->isFull()) {
- clearBlocked((BlockedCause)mq->index);
+ mshrQueue.deallocate(mshr);
+ if (wasFull && !mshrQueue.isFull()) {
+ clearBlocked(Blocked_NoMSHRs);
}
// Request the bus for a prefetch if this deallocation freed enough
// MSHRs for a prefetch to take place
- if (prefetcher && mq == &mshrQueue && mshrQueue.canPrefetch()) {
+ if (prefetcher && mshrQueue.canPrefetch()) {
Tick next_pf_time = std::max(prefetcher->nextPrefetchReadyTime(),
clockEdge());
if (next_pf_time != MaxTick)
@@ -1715,11 +1747,9 @@ Cache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks,
CacheBlk::State old_state = blk ? blk->status : 0;
#endif
- // When handling a fill, discard any CleanEvicts for the
- // same address in write buffer.
- Addr M5_VAR_USED blk_addr = blockAlign(pkt->getAddr());
- std::vector<MSHR *> M5_VAR_USED wbs;
- assert (!writeBuffer.findMatches(blk_addr, is_secure, wbs));
+ // When handling a fill, we should have no writes to this line.
+ assert(addr == blockAlign(addr));
+ assert(!writeBuffer.findMatch(addr, is_secure));
if (blk == NULL) {
// better have read new data...
@@ -2107,15 +2137,10 @@ Cache::recvTimingSnoopReq(PacketPtr pkt)
}
//We also need to check the writeback buffers and handle those
- std::vector<MSHR *> writebacks;
- if (writeBuffer.findMatches(blk_addr, is_secure, writebacks)) {
+ WriteQueueEntry *wb_entry = writeBuffer.findMatch(blk_addr, is_secure);
+ if (wb_entry) {
DPRINTF(Cache, "Snoop hit in writeback to addr %#llx (%s)\n",
pkt->getAddr(), is_secure ? "s" : "ns");
-
- // Look through writebacks for any cachable writes.
- // We should only ever find a single match
- assert(writebacks.size() == 1);
- MSHR *wb_entry = writebacks[0];
// Expect to see only Writebacks and/or CleanEvicts here, both of
// which should not be generated for uncacheable data.
assert(!wb_entry->isUncacheable());
@@ -2166,7 +2191,7 @@ Cache::recvTimingSnoopReq(PacketPtr pkt)
if (invalidate) {
// Invalidation trumps our writeback... discard here
// Note: markInService will remove entry from writeback buffer.
- markInService(wb_entry, false);
+ markInService(wb_entry);
delete wb_pkt;
}
}
@@ -2209,26 +2234,28 @@ Cache::recvAtomicSnoop(PacketPtr pkt)
}
-MSHR *
-Cache::getNextMSHR()
+QueueEntry*
+Cache::getNextQueueEntry()
{
// Check both MSHR queue and write buffer for potential requests,
// note that null does not mean there is no request, it could
// simply be that it is not ready
- MSHR *miss_mshr = mshrQueue.getNextMSHR();
- MSHR *write_mshr = writeBuffer.getNextMSHR();
+ MSHR *miss_mshr = mshrQueue.getNext();
+ WriteQueueEntry *wq_entry = writeBuffer.getNext();
// If we got a write buffer request ready, first priority is a
- // full write buffer, otherwhise we favour the miss requests
- if (write_mshr &&
- ((writeBuffer.isFull() && writeBuffer.inServiceEntries == 0) ||
+ // full write buffer (but only if we have no uncacheable write
+ // responses outstanding, possibly revisit this last part),
+ // otherwhise we favour the miss requests
+ if (wq_entry &&
+ ((writeBuffer.isFull() && writeBuffer.numInService() == 0) ||
!miss_mshr)) {
// need to search MSHR queue for conflicting earlier miss.
MSHR *conflict_mshr =
- mshrQueue.findPending(write_mshr->blkAddr,
- write_mshr->isSecure);
+ mshrQueue.findPending(wq_entry->blkAddr,
+ wq_entry->isSecure);
- if (conflict_mshr && conflict_mshr->order < write_mshr->order) {
+ if (conflict_mshr && conflict_mshr->order < wq_entry->order) {
// Service misses in order until conflict is cleared.
return conflict_mshr;
@@ -2236,10 +2263,10 @@ Cache::getNextMSHR()
}
// No conflicts; issue write
- return write_mshr;
+ return wq_entry;
} else if (miss_mshr) {
// need to check for conflicting earlier writeback
- MSHR *conflict_mshr =
+ WriteQueueEntry *conflict_mshr =
writeBuffer.findPending(miss_mshr->blkAddr,
miss_mshr->isSecure);
if (conflict_mshr) {
@@ -2252,7 +2279,7 @@ Cache::getNextMSHR()
// We need to make sure to perform the writeback first
// To preserve the dirty data, then we can issue the write
- // should we return write_mshr here instead? I.e. do we
+ // should we return wq_entry here instead? I.e. do we
// have to flush writes in order? I don't think so... not
// for Alpha anyway. Maybe for x86?
return conflict_mshr;
@@ -2265,7 +2292,7 @@ Cache::getNextMSHR()
}
// fall through... no pending requests. Try a prefetch.
- assert(!miss_mshr && !write_mshr);
+ assert(!miss_mshr && !wq_entry);
if (prefetcher && mshrQueue.canPrefetch()) {
// If we have a miss queue slot, we can try a prefetch
PacketPtr pkt = prefetcher->getPacket();
@@ -2291,7 +2318,7 @@ Cache::getNextMSHR()
}
}
- return NULL;
+ return nullptr;
}
bool
@@ -2322,25 +2349,41 @@ Cache::isCachedAbove(PacketPtr pkt, bool is_timing) const
}
}
-PacketPtr
-Cache::getTimingPacket()
+Tick
+Cache::nextQueueReadyTime() const
{
- MSHR *mshr = getNextMSHR();
+ Tick nextReady = std::min(mshrQueue.nextReadyTime(),
+ writeBuffer.nextReadyTime());
- if (mshr == NULL) {
- return NULL;
+ // Don't signal prefetch ready time if no MSHRs available
+ // Will signal once enoguh MSHRs are deallocated
+ if (prefetcher && mshrQueue.canPrefetch()) {
+ nextReady = std::min(nextReady,
+ prefetcher->nextPrefetchReadyTime());
}
+ return nextReady;
+}
+
+bool
+Cache::sendMSHRQueuePacket(MSHR* mshr)
+{
+ assert(mshr);
+
// use request from 1st target
PacketPtr tgt_pkt = mshr->getTarget()->pkt;
- PacketPtr pkt = NULL;
- DPRINTF(CachePort, "%s %s for addr %#llx size %d\n", __func__,
- tgt_pkt->cmdString(), tgt_pkt->getAddr(), tgt_pkt->getSize());
+ DPRINTF(Cache, "%s MSHR %s for addr %#llx size %d\n", __func__,
+ tgt_pkt->cmdString(), tgt_pkt->getAddr(),
+ tgt_pkt->getSize());
CacheBlk *blk = tags->findBlock(mshr->blkAddr, mshr->isSecure);
if (tgt_pkt->cmd == MemCmd::HardPFReq && forwardSnoops) {
+ // we should never have hardware prefetches to allocated
+ // blocks
+ assert(blk == NULL);
+
// We need to check the caches above us to verify that
// they don't have a copy of this block in the dirty state
// at the moment. Without this check we could get a stale
@@ -2379,65 +2422,119 @@ Cache::getTimingPacket()
DPRINTF(Cache, "Upward snoop of prefetch for addr"
" %#x (%s) hit\n",
tgt_pkt->getAddr(), tgt_pkt->isSecure()? "s": "ns");
- return NULL;
+ return false;
}
- if (snoop_pkt.isBlockCached() || blk != NULL) {
+ if (snoop_pkt.isBlockCached()) {
DPRINTF(Cache, "Block present, prefetch squashed by cache. "
"Deallocating mshr target %#x.\n",
mshr->blkAddr);
+
// Deallocate the mshr target
- if (mshr->queue->forceDeallocateTarget(mshr)) {
+ if (mshrQueue.forceDeallocateTarget(mshr)) {
// Clear block if this deallocation resulted freed an
// mshr when all had previously been utilized
- clearBlocked((BlockedCause)(mshr->queue->index));
+ clearBlocked(Blocked_NoMSHRs);
}
- return NULL;
+ return false;
}
}
- if (mshr->isForwardNoResponse()) {
- // no response expected, just forward packet as it is
- assert(tags->findBlock(mshr->blkAddr, mshr->isSecure) == NULL);
- pkt = tgt_pkt;
- } else {
- pkt = getBusPacket(tgt_pkt, blk, mshr->needsWritable());
+ // either a prefetch that is not present upstream, or a normal
+ // MSHR request, proceed to get the packet to send downstream
+ PacketPtr pkt = getBusPacket(tgt_pkt, blk, mshr->needsWritable());
- mshr->isForward = (pkt == NULL);
+ mshr->isForward = (pkt == NULL);
- if (mshr->isForward) {
- // not a cache block request, but a response is expected
- // make copy of current packet to forward, keep current
- // copy for response handling
- pkt = new Packet(tgt_pkt, false, true);
- if (pkt->isWrite()) {
- pkt->setData(tgt_pkt->getConstPtr<uint8_t>());
- }
- }
+ if (mshr->isForward) {
+ // not a cache block request, but a response is expected
+ // make copy of current packet to forward, keep current
+ // copy for response handling
+ pkt = new Packet(tgt_pkt, false, true);
+ assert(!pkt->isWrite());
}
- assert(pkt != NULL);
- // play it safe and append (rather than set) the sender state, as
- // forwarded packets may already have existing state
+ // play it safe and append (rather than set) the sender state,
+ // as forwarded packets may already have existing state
pkt->pushSenderState(mshr);
- return pkt;
-}
+ if (!memSidePort->sendTimingReq(pkt)) {
+ // we are awaiting a retry, but we
+ // delete the packet and will be creating a new packet
+ // when we get the opportunity
+ delete pkt;
-Tick
-Cache::nextMSHRReadyTime() const
+ // note that we have now masked any requestBus and
+ // schedSendEvent (we will wait for a retry before
+ // doing anything), and this is so even if we do not
+ // care about this packet and might override it before
+ // it gets retried
+ return true;
+ } else {
+ // As part of the call to sendTimingReq the packet is
+ // forwarded to all neighbouring caches (and any caches
+ // above them) as a snoop. Thus at this point we know if
+ // any of the neighbouring caches are responding, and if
+ // so, we know it is dirty, and we can determine if it is
+ // being passed as Modified, making our MSHR the ordering
+ // point
+ bool pending_modified_resp = !pkt->hasSharers() &&
+ pkt->cacheResponding();
+ markInService(mshr, pending_modified_resp);
+ return false;
+ }
+}
+
+bool
+Cache::sendWriteQueuePacket(WriteQueueEntry* wq_entry)
{
- Tick nextReady = std::min(mshrQueue.nextMSHRReadyTime(),
- writeBuffer.nextMSHRReadyTime());
+ assert(wq_entry);
- // Don't signal prefetch ready time if no MSHRs available
- // Will signal once enoguh MSHRs are deallocated
- if (prefetcher && mshrQueue.canPrefetch()) {
- nextReady = std::min(nextReady,
- prefetcher->nextPrefetchReadyTime());
- }
+ // always a single target for write queue entries
+ PacketPtr tgt_pkt = wq_entry->getTarget()->pkt;
- return nextReady;
+ DPRINTF(Cache, "%s write %s for addr %#llx size %d\n", __func__,
+ tgt_pkt->cmdString(), tgt_pkt->getAddr(),
+ tgt_pkt->getSize());
+
+ PacketPtr pkt = nullptr;
+ bool delete_pkt = false;
+
+ if (tgt_pkt->isEviction()) {
+ assert(!wq_entry->isUncacheable());
+ // no response expected, just forward packet as it is
+ pkt = tgt_pkt;
+ } else {
+ // the only thing we deal with besides eviction commands
+ // are uncacheable writes
+ assert(tgt_pkt->req->isUncacheable() && tgt_pkt->isWrite());
+ // not a cache block request, but a response is expected
+ // make copy of current packet to forward, keep current
+ // copy for response handling
+ pkt = new Packet(tgt_pkt, false, true);
+ pkt->setData(tgt_pkt->getConstPtr<uint8_t>());
+ delete_pkt = true;
+ }
+
+ pkt->pushSenderState(wq_entry);
+
+ if (!memSidePort->sendTimingReq(pkt)) {
+ if (delete_pkt) {
+ // we are awaiting a retry, but we
+ // delete the packet and will be creating a new packet
+ // when we get the opportunity
+ delete pkt;
+ }
+ // note that we have now masked any requestBus and
+ // schedSendEvent (we will wait for a retry before
+ // doing anything), and this is so even if we do not
+ // care about this packet and might override it before
+ // it gets retried
+ return true;
+ } else {
+ markInService(wq_entry);
+ return false;
+ }
}
void
@@ -2586,71 +2683,27 @@ Cache::CacheReqPacketQueue::sendDeferredPacket()
assert(deferredPacketReadyTime() == MaxTick);
// check for request packets (requests & writebacks)
- PacketPtr pkt = cache.getTimingPacket();
- if (pkt == NULL) {
+ QueueEntry* entry = cache.getNextQueueEntry();
+
+ if (!entry) {
// can happen if e.g. we attempt a writeback and fail, but
// before the retry, the writeback is eliminated because
// we snoop another cache's ReadEx.
} else {
- MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
- // in most cases getTimingPacket allocates a new packet, and
- // we must delete it unless it is successfully sent
- bool delete_pkt = !mshr->isForwardNoResponse();
-
// let our snoop responses go first if there are responses to
- // the same addresses we are about to writeback, note that
- // this creates a dependency between requests and snoop
- // responses, but that should not be a problem since there is
- // a chain already and the key is that the snoop responses can
- // sink unconditionally
- if (snoopRespQueue.hasAddr(pkt->getAddr())) {
- DPRINTF(CachePort, "Waiting for snoop response to be sent\n");
- Tick when = snoopRespQueue.deferredPacketReadyTime();
- schedSendEvent(when);
-
- if (delete_pkt)
- delete pkt;
-
+ // the same addresses
+ if (checkConflictingSnoop(entry->blkAddr)) {
return;
}
-
-
- waitingOnRetry = !masterPort.sendTimingReq(pkt);
-
- if (waitingOnRetry) {
- DPRINTF(CachePort, "now waiting on a retry\n");
- if (delete_pkt) {
- // we are awaiting a retry, but we
- // delete the packet and will be creating a new packet
- // when we get the opportunity
- delete pkt;
- }
- // note that we have now masked any requestBus and
- // schedSendEvent (we will wait for a retry before
- // doing anything), and this is so even if we do not
- // care about this packet and might override it before
- // it gets retried
- } else {
- // As part of the call to sendTimingReq the packet is
- // forwarded to all neighbouring caches (and any caches
- // above them) as a snoop. Thus at this point we know if
- // any of the neighbouring caches are responding, and if
- // so, we know it is dirty, and we can determine if it is
- // being passed as Modified, making our MSHR the ordering
- // point
- bool pending_modified_resp = !pkt->hasSharers() &&
- pkt->cacheResponding();
-
- cache.markInService(mshr, pending_modified_resp);
- }
+ waitingOnRetry = entry->sendPacket(cache);
}
// if we succeeded and are not waiting for a retry, schedule the
- // next send considering when the next MSHR is ready, note that
+ // next send considering when the next queue is ready, note that
// snoop responses have their own packet queue and thus schedule
// their own events
if (!waitingOnRetry) {
- schedSendEvent(cache.nextMSHRReadyTime());
+ schedSendEvent(cache.nextQueueReadyTime());
}
}
diff --git a/src/mem/cache/cache.hh b/src/mem/cache/cache.hh
index a1ab66ab1..f2288bd7c 100644
--- a/src/mem/cache/cache.hh
+++ b/src/mem/cache/cache.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012-2015 ARM Limited
+ * Copyright (c) 2012-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -137,6 +137,23 @@ class Cache : public BaseCache
*/
virtual void sendDeferredPacket();
+ /**
+ * Check if there is a conflicting snoop response about to be
+ * send out, and if so simply stall any requests, and schedule
+ * a send event at the same time as the next snoop response is
+ * being sent out.
+ */
+ bool checkConflictingSnoop(Addr addr)
+ {
+ if (snoopRespQueue.hasAddr(addr)) {
+ DPRINTF(CachePort, "Waiting for snoop response to be "
+ "sent\n");
+ Tick when = snoopRespQueue.deferredPacketReadyTime();
+ schedSendEvent(when);
+ return true;
+ }
+ return false;
+ }
};
/**
@@ -339,6 +356,12 @@ class Cache : public BaseCache
void doWritebacksAtomic(PacketList& writebacks);
/**
+ * Handling the special case of uncacheable write responses to
+ * make recvTimingResp less cluttered.
+ */
+ void handleUncacheableWriteResp(PacketPtr pkt);
+
+ /**
* Handles a response (cache line fill/write ack) from the bus.
* @param pkt The response packet
*/
@@ -451,12 +474,12 @@ class Cache : public BaseCache
bool needsExclusive) const;
/**
- * Return the next MSHR to service, either a pending miss from the
- * mshrQueue, a buffered write from the write buffer, or something
- * from the prefetcher. This function is responsible for
- * prioritizing among those sources on the fly.
+ * Return the next queue entry to service, either a pending miss
+ * from the MSHR queue, a buffered write from the write buffer, or
+ * something from the prefetcher. This function is responsible
+ * for prioritizing among those sources on the fly.
*/
- MSHR *getNextMSHR();
+ QueueEntry* getNextQueueEntry();
/**
* Send up a snoop request and find cached copies. If cached copies are
@@ -465,28 +488,11 @@ class Cache : public BaseCache
bool isCachedAbove(PacketPtr pkt, bool is_timing = true) const;
/**
- * Selects an outstanding request to service. Called when the
- * cache gets granted the downstream bus in timing mode.
- * @return The request to service, NULL if none found.
- */
- PacketPtr getTimingPacket();
-
- /**
- * Marks a request as in service (sent downstream in the memory
- * system). This can have side effect since storage for no
- * response commands is deallocated once they are successfully
- * sent. Also remember if we are expecting a Modified (dirty and
- * writable) response from another cache, effectively making this
- * MSHR the ordering point.
- */
- void markInService(MSHR *mshr, bool pending_modified_resp);
-
- /**
* Return whether there are any outstanding misses.
*/
bool outstandingMisses() const
{
- return mshrQueue.allocated != 0;
+ return !mshrQueue.isEmpty();
}
CacheBlk *findBlock(Addr addr, bool is_secure) const {
@@ -504,7 +510,7 @@ class Cache : public BaseCache
/**
* Find next request ready time from among possible sources.
*/
- Tick nextMSHRReadyTime() const;
+ Tick nextQueueReadyTime() const;
public:
/** Instantiates a basic cache object. */
@@ -515,6 +521,26 @@ class Cache : public BaseCache
void regStats() override;
+ /**
+ * Take an MSHR, turn it into a suitable downstream packet, and
+ * send it out. This construct allows a queue entry to choose a suitable
+ * approach based on its type.
+ *
+ * @param mshr The MSHR to turn into a packet and send
+ * @return True if the port is waiting for a retry
+ */
+ bool sendMSHRQueuePacket(MSHR* mshr);
+
+ /**
+ * Similar to sendMSHR, but for a write-queue entry
+ * instead. Create the packet, and send it, and if successful also
+ * mark the entry in service.
+ *
+ * @param wq_entry The write-queue entry to turn into a packet and send
+ * @return True if the port is waiting for a retry
+ */
+ bool sendWriteQueuePacket(WriteQueueEntry* wq_entry);
+
/** serialize the state of the caches
* We currently don't support checkpointing cache state, so this panics.
*/
diff --git a/src/mem/cache/mshr.cc b/src/mem/cache/mshr.cc
index 1d18a2861..14f381e91 100644
--- a/src/mem/cache/mshr.cc
+++ b/src/mem/cache/mshr.cc
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012-2013, 2015 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -61,17 +61,13 @@
using namespace std;
-MSHR::MSHR() : readyTime(0), _isUncacheable(false), downstreamPending(false),
+MSHR::MSHR() : downstreamPending(false),
pendingModified(false),
postInvalidate(false), postDowngrade(false),
- queue(NULL), order(0), blkAddr(0),
- blkSize(0), isSecure(false), inService(false),
- isForward(false), allocOnFill(false),
- data(NULL)
+ isForward(false), allocOnFill(false)
{
}
-
MSHR::TargetList::TargetList()
: needsWritable(false), hasUpgrade(false)
{}
@@ -239,7 +235,6 @@ MSHR::allocate(Addr blk_addr, unsigned blk_size, PacketPtr target,
Target::FromPrefetcher : Target::FromCPU;
targets.add(target, when_ready, _order, source, true);
assert(deferredTargets.isReset());
- data = NULL;
}
@@ -253,17 +248,10 @@ MSHR::clearDownstreamPending()
targets.clearDownstreamPending();
}
-bool
+void
MSHR::markInService(bool pending_modified_resp)
{
assert(!inService);
- if (isForwardNoResponse()) {
- // we just forwarded the request packet & don't expect a
- // response, so get rid of it
- assert(getNumTargets() == 1);
- popTarget();
- return true;
- }
inService = true;
pendingModified = targets.needsWritable || pending_modified_resp;
@@ -274,7 +262,6 @@ MSHR::markInService(bool pending_modified_resp)
// level where it's going to get a response
targets.clearDownstreamPending();
}
- return false;
}
@@ -512,6 +499,11 @@ MSHR::checkFunctional(PacketPtr pkt)
}
}
+bool
+MSHR::sendPacket(Cache &cache)
+{
+ return cache.sendMSHRQueuePacket(this);
+}
void
MSHR::print(std::ostream &os, int verbosity, const std::string &prefix) const
@@ -521,7 +513,6 @@ MSHR::print(std::ostream &os, int verbosity, const std::string &prefix) const
isSecure ? "s" : "ns",
isForward ? "Forward" : "",
allocOnFill ? "AllocOnFill" : "",
- isForwardNoResponse() ? "ForwNoResp" : "",
needsWritable() ? "Wrtbl" : "",
_isUncacheable ? "Unc" : "",
inService ? "InSvc" : "",
diff --git a/src/mem/cache/mshr.hh b/src/mem/cache/mshr.hh
index ea3719343..146e5e47a 100644
--- a/src/mem/cache/mshr.hh
+++ b/src/mem/cache/mshr.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012-2013, 2015 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -51,32 +51,27 @@
#include <list>
#include "base/printable.hh"
-#include "mem/packet.hh"
+#include "mem/cache/queue_entry.hh"
-class CacheBlk;
-class MSHRQueue;
+class Cache;
/**
* Miss Status and handling Register. This class keeps all the information
* needed to handle a cache miss including a list of target requests.
* @sa \ref gem5MemorySystem "gem5 Memory System"
*/
-class MSHR : public Packet::SenderState, public Printable
+class MSHR : public QueueEntry, public Printable
{
/**
- * Consider the MSHRQueue a friend to avoid making everything public
+ * Consider the queues friends to avoid making everything public.
*/
+ template<typename Entry>
+ friend class Queue;
friend class MSHRQueue;
private:
- /** Cycle when ready to issue */
- Tick readyTime;
-
- /** True if the request is uncacheable */
- bool _isUncacheable;
-
/** Flag set by downstream caches */
bool downstreamPending;
@@ -114,6 +109,9 @@ class MSHR : public Packet::SenderState, public Printable
public:
+ /** True if the entry is just a simple forward from an upper level */
+ bool isForward;
+
class Target {
public:
@@ -166,29 +164,6 @@ class MSHR : public Packet::SenderState, public Printable
typedef std::list<MSHR *> List;
/** MSHR list iterator. */
typedef List::iterator Iterator;
- /** MSHR list const_iterator. */
- typedef List::const_iterator ConstIterator;
-
- /** Pointer to queue containing this MSHR. */
- MSHRQueue *queue;
-
- /** Order number assigned by the miss queue. */
- Counter order;
-
- /** Block aligned address of the MSHR. */
- Addr blkAddr;
-
- /** Block size of the cache. */
- unsigned blkSize;
-
- /** True if the request targets the secure memory space. */
- bool isSecure;
-
- /** True if the request has been sent to the bus. */
- bool inService;
-
- /** True if the request is just a simple forward from an upper level */
- bool isForward;
/** Keep track of whether we should allocate on fill or not */
bool allocOnFill;
@@ -213,11 +188,9 @@ class MSHR : public Packet::SenderState, public Printable
assert(inService); return postDowngrade;
}
- private:
+ bool sendPacket(Cache &cache);
- /** Data buffer (if needed). Currently used only for pending
- * upgrade handling. */
- uint8_t *data;
+ private:
/**
* Pointer to this MSHR on the ready list.
@@ -238,8 +211,6 @@ class MSHR : public Packet::SenderState, public Printable
public:
- bool isUncacheable() const { return _isUncacheable; }
-
/**
* Allocate a miss to this MSHR.
* @param blk_addr The address of the block.
@@ -252,7 +223,7 @@ class MSHR : public Packet::SenderState, public Printable
void allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
Tick when_ready, Counter _order, bool alloc_on_fill);
- bool markInService(bool pending_modified_resp);
+ void markInService(bool pending_modified_resp);
void clearDownstreamPending();
@@ -303,14 +274,6 @@ class MSHR : public Packet::SenderState, public Printable
targets.pop_front();
}
- bool isForwardNoResponse() const
- {
- if (getNumTargets() != 1)
- return false;
- const Target *tgt = &targets.front();
- return tgt->source == Target::FromCPU && !tgt->pkt->needsResponse();
- }
-
bool promoteDeferredTargets();
void promoteWritable();
diff --git a/src/mem/cache/mshr_queue.cc b/src/mem/cache/mshr_queue.cc
index ed6769349..f4992e176 100644
--- a/src/mem/cache/mshr_queue.cc
+++ b/src/mem/cache/mshr_queue.cc
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012-2013, 2015 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -45,104 +45,15 @@
* Definition of MSHRQueue class functions.
*/
-#include "base/trace.hh"
#include "mem/cache/mshr_queue.hh"
-#include "debug/Drain.hh"
using namespace std;
MSHRQueue::MSHRQueue(const std::string &_label,
- int num_entries, int reserve, int demand_reserve,
- int _index)
- : label(_label), numEntries(num_entries + reserve - 1),
- numReserve(reserve), demandReserve(demand_reserve),
- registers(numEntries), allocated(0),
- inServiceEntries(0), index(_index)
-{
- for (int i = 0; i < numEntries; ++i) {
- registers[i].queue = this;
- freeList.push_back(&registers[i]);
- }
-}
-
-MSHR *
-MSHRQueue::findMatch(Addr blk_addr, bool is_secure) const
-{
- for (const auto& mshr : allocatedList) {
- // we ignore any MSHRs allocated for uncacheable accesses and
- // simply ignore them when matching, in the cache we never
- // check for matches when adding new uncacheable entries, and
- // we do not want normal cacheable accesses being added to an
- // MSHR serving an uncacheable access
- if (!mshr->isUncacheable() && mshr->blkAddr == blk_addr &&
- mshr->isSecure == is_secure) {
- return mshr;
- }
- }
- return NULL;
-}
-
-bool
-MSHRQueue::findMatches(Addr blk_addr, bool is_secure,
- vector<MSHR*>& matches) const
-{
- // Need an empty vector
- assert(matches.empty());
- bool retval = false;
- for (const auto& mshr : allocatedList) {
- if (!mshr->isUncacheable() && mshr->blkAddr == blk_addr &&
- mshr->isSecure == is_secure) {
- retval = true;
- matches.push_back(mshr);
- }
- }
- return retval;
-}
-
-
-bool
-MSHRQueue::checkFunctional(PacketPtr pkt, Addr blk_addr)
-{
- pkt->pushLabel(label);
- for (const auto& mshr : allocatedList) {
- if (mshr->blkAddr == blk_addr && mshr->checkFunctional(pkt)) {
- pkt->popLabel();
- return true;
- }
- }
- pkt->popLabel();
- return false;
-}
-
-
-MSHR *
-MSHRQueue::findPending(Addr blk_addr, bool is_secure) const
-{
- for (const auto& mshr : readyList) {
- if (mshr->blkAddr == blk_addr && mshr->isSecure == is_secure) {
- return mshr;
- }
- }
- return NULL;
-}
-
-
-MSHR::Iterator
-MSHRQueue::addToReadyList(MSHR *mshr)
-{
- if (readyList.empty() || readyList.back()->readyTime <= mshr->readyTime) {
- return readyList.insert(readyList.end(), mshr);
- }
-
- for (auto i = readyList.begin(); i != readyList.end(); ++i) {
- if ((*i)->readyTime > mshr->readyTime) {
- return readyList.insert(i, mshr);
- }
- }
- assert(false);
- return readyList.end(); // keep stupid compilers happy
-}
-
+ int num_entries, int reserve, int demand_reserve)
+ : Queue<MSHR>(_label, num_entries, reserve),
+ demandReserve(demand_reserve)
+{}
MSHR *
MSHRQueue::allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
@@ -161,34 +72,6 @@ MSHRQueue::allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
return mshr;
}
-
-void
-MSHRQueue::deallocate(MSHR *mshr)
-{
- deallocateOne(mshr);
-}
-
-MSHR::Iterator
-MSHRQueue::deallocateOne(MSHR *mshr)
-{
- MSHR::Iterator retval = allocatedList.erase(mshr->allocIter);
- freeList.push_front(mshr);
- allocated--;
- if (mshr->inService) {
- inServiceEntries--;
- } else {
- readyList.erase(mshr->readyIter);
- }
- mshr->deallocate();
- if (drainState() == DrainState::Draining && allocated == 0) {
- // Notify the drain manager that we have completed draining if
- // there are no other outstanding requests in this MSHR queue.
- DPRINTF(Drain, "MSHRQueue now empty, signalling drained\n");
- signalDrainDone();
- }
- return retval;
-}
-
void
MSHRQueue::moveToFront(MSHR *mshr)
{
@@ -202,12 +85,9 @@ MSHRQueue::moveToFront(MSHR *mshr)
void
MSHRQueue::markInService(MSHR *mshr, bool pending_modified_resp)
{
- if (mshr->markInService(pending_modified_resp)) {
- deallocate(mshr);
- } else {
- readyList.erase(mshr->readyIter);
- inServiceEntries += 1;
- }
+ mshr->markInService(pending_modified_resp);
+ readyList.erase(mshr->readyIter);
+ _numInService += 1;
}
void
@@ -215,7 +95,7 @@ MSHRQueue::markPending(MSHR *mshr)
{
assert(mshr->inService);
mshr->inService = false;
- --inServiceEntries;
+ --_numInService;
/**
* @ todo might want to add rerequests to front of pending list for
* performance.
@@ -232,15 +112,9 @@ MSHRQueue::forceDeallocateTarget(MSHR *mshr)
mshr->popTarget();
// Delete mshr if no remaining targets
if (!mshr->hasTargets() && !mshr->promoteDeferredTargets()) {
- deallocateOne(mshr);
+ deallocate(mshr);
}
// Notify if MSHR queue no longer full
return was_full && !isFull();
}
-
-DrainState
-MSHRQueue::drain()
-{
- return allocated == 0 ? DrainState::Drained : DrainState::Draining;
-}
diff --git a/src/mem/cache/mshr_queue.hh b/src/mem/cache/mshr_queue.hh
index 45aa1c15f..ff78cbebb 100644
--- a/src/mem/cache/mshr_queue.hh
+++ b/src/mem/cache/mshr_queue.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012-2013, 2015 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
@@ -51,31 +51,14 @@
#include <vector>
#include "mem/cache/mshr.hh"
-#include "mem/packet.hh"
-#include "sim/drain.hh"
+#include "mem/cache/queue.hh"
/**
* A Class for maintaining a list of pending and allocated memory requests.
*/
-class MSHRQueue : public Drainable
+class MSHRQueue : public Queue<MSHR>
{
private:
- /** Local label (for functional print requests) */
- const std::string label;
-
- // Parameters
- /**
- * The total number of entries in this queue. This number is set as the
- * number of entries requested plus (numReserve - 1). This allows for
- * the same number of effective entries while still maintaining the reserve.
- */
- const int numEntries;
-
- /**
- * The number of entries to hold in reserve. This is needed because copy
- * operations can allocate upto 4 entries at one time.
- */
- const int numReserve;
/**
* The number of entries to reserve for future demand accesses.
@@ -83,26 +66,7 @@ class MSHRQueue : public Drainable
*/
const int demandReserve;
- /** MSHR storage. */
- std::vector<MSHR> registers;
- /** Holds pointers to all allocated entries. */
- MSHR::List allocatedList;
- /** Holds pointers to entries that haven't been sent to the bus. */
- MSHR::List readyList;
- /** Holds non allocated entries. */
- MSHR::List freeList;
-
- MSHR::Iterator addToReadyList(MSHR *mshr);
-
-
public:
- /** The number of allocated entries. */
- int allocated;
- /** The number of entries that have been forwarded to the bus. */
- int inServiceEntries;
- /** The index of this queue within the cache (MSHR queue vs. write
- * buffer). */
- const int index;
/**
* Create a queue with a given number of entries.
@@ -113,35 +77,7 @@ class MSHRQueue : public Drainable
* demand accesses.
*/
MSHRQueue(const std::string &_label, int num_entries, int reserve,
- int demand_reserve, int index);
-
- /**
- * Find the first MSHR that matches the provided address.
- * @param blk_addr The block address to find.
- * @param is_secure True if the target memory space is secure.
- * @return Pointer to the matching MSHR, null if not found.
- */
- MSHR *findMatch(Addr blk_addr, bool is_secure) const;
-
- /**
- * Find and return all the matching entries in the provided vector.
- * @param blk_addr The block address to find.
- * @param is_secure True if the target memory space is secure.
- * @param matches The vector to return pointers to the matching entries.
- * @return True if any matches are found, false otherwise.
- */
- bool findMatches(Addr blk_addr, bool is_secure,
- std::vector<MSHR*>& matches) const;
-
- /**
- * Find any pending requests that overlap the given request.
- * @param blk_addr Block address.
- * @param is_secure True if the target memory space is secure.
- * @return A pointer to the earliest matching MSHR.
- */
- MSHR *findPending(Addr blk_addr, bool is_secure) const;
-
- bool checkFunctional(PacketPtr pkt, Addr blk_addr);
+ int demand_reserve);
/**
* Allocates a new MSHR for the request and size. This places the request
@@ -162,21 +98,6 @@ class MSHRQueue : public Drainable
Tick when_ready, Counter order, bool alloc_on_fill);
/**
- * Removes the given MSHR from the queue. This places the MSHR on the
- * free list.
- * @param mshr
- */
- void deallocate(MSHR *mshr);
-
- /**
- * Remove a MSHR from the queue. Returns an iterator into the
- * allocatedList.
- * @param mshr The MSHR to remove.
- * @return An iterator to the next entry in the allocatedList.
- */
- MSHR::Iterator deallocateOne(MSHR *mshr);
-
- /**
* Moves the MSHR to the front of the pending list if it is not
* in service.
* @param mshr The entry to move.
@@ -215,15 +136,6 @@ class MSHRQueue : public Drainable
}
/**
- * Returns true if there are no free entries.
- * @return True if this queue is full.
- */
- bool isFull() const
- {
- return (allocated > numEntries - numReserve);
- }
-
- /**
* Returns true if sufficient mshrs for prefetch.
* @return True if sufficient mshrs for prefetch.
*/
@@ -231,25 +143,6 @@ class MSHRQueue : public Drainable
{
return (allocated < numEntries - (numReserve + demandReserve));
}
-
- /**
- * Returns the MSHR at the head of the readyList.
- * @return The next request to service.
- */
- MSHR *getNextMSHR() const
- {
- if (readyList.empty() || readyList.front()->readyTime > curTick()) {
- return NULL;
- }
- return readyList.front();
- }
-
- Tick nextMSHRReadyTime() const
- {
- return readyList.empty() ? MaxTick : readyList.front()->readyTime;
- }
-
- DrainState drain() override;
};
#endif //__MEM_CACHE_MSHR_QUEUE_HH__
diff --git a/src/mem/cache/queue.hh b/src/mem/cache/queue.hh
new file mode 100644
index 000000000..11d456e11
--- /dev/null
+++ b/src/mem/cache/queue.hh
@@ -0,0 +1,251 @@
+/*
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder. You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2003-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Erik Hallnor
+ * Andreas Sandberg
+ * Andreas Hansson
+ */
+
+/** @file
+ * Declaration of a high-level queue structure
+ */
+
+#ifndef __MEM_CACHE_QUEUE_HH__
+#define __MEM_CACHE_QUEUE_HH__
+
+#include <cassert>
+
+#include "base/trace.hh"
+#include "debug/Drain.hh"
+#include "mem/cache/queue_entry.hh"
+#include "sim/drain.hh"
+
+/**
+ * A high-level queue interface, to be used by both the MSHR queue and
+ * the write buffer.
+ */
+template<class Entry>
+class Queue : public Drainable
+{
+ protected:
+ /** Local label (for functional print requests) */
+ const std::string label;
+
+ /**
+ * The total number of entries in this queue. This number is set
+ * as the number of entries requested plus (numReserve - 1). This
+ * allows for the same number of effective entries while still
+ * maintaining an overflow reserve.
+ */
+ const int numEntries;
+
+ /**
+ * The number of entries to hold as a temporary overflow
+ * space. This is used to allow temporary overflow of the number
+ * of entries as we only check the full condition under certain
+ * conditions.
+ */
+ const int numReserve;
+
+ /** Actual storage. */
+ std::vector<Entry> entries;
+ /** Holds pointers to all allocated entries. */
+ typename Entry::List allocatedList;
+ /** Holds pointers to entries that haven't been sent downstream. */
+ typename Entry::List readyList;
+ /** Holds non allocated entries. */
+ typename Entry::List freeList;
+
+ typename Entry::Iterator addToReadyList(Entry* entry)
+ {
+ if (readyList.empty() ||
+ readyList.back()->readyTime <= entry->readyTime) {
+ return readyList.insert(readyList.end(), entry);
+ }
+
+ for (auto i = readyList.begin(); i != readyList.end(); ++i) {
+ if ((*i)->readyTime > entry->readyTime) {
+ return readyList.insert(i, entry);
+ }
+ }
+ assert(false);
+ return readyList.end(); // keep stupid compilers happy
+ }
+
+ /** The number of entries that are in service. */
+ int _numInService;
+
+ /** The number of currently allocated entries. */
+ int allocated;
+
+ public:
+
+ /**
+ * Create a queue with a given number of entries.
+ *
+ * @param num_entries The number of entries in this queue.
+ * @param num_overflow The extra overflow entries needed.
+ */
+ Queue(const std::string &_label, int num_entries, int reserve) :
+ label(_label), numEntries(num_entries + reserve - 1),
+ numReserve(reserve), entries(numEntries), _numInService(0),
+ allocated(0)
+ {
+ for (int i = 0; i < numEntries; ++i) {
+ freeList.push_back(&entries[i]);
+ }
+ }
+
+ bool isEmpty() const
+ {
+ return allocated == 0;
+ }
+
+ bool isFull() const
+ {
+ return (allocated > numEntries - numReserve);
+ }
+
+ int numInService() const
+ {
+ return _numInService;
+ }
+
+ /**
+ * Find the first WriteQueueEntry that matches the provided address.
+ * @param blk_addr The block address to find.
+ * @param is_secure True if the target memory space is secure.
+ * @return Pointer to the matching WriteQueueEntry, null if not found.
+ */
+ Entry* findMatch(Addr blk_addr, bool is_secure) const
+ {
+ for (const auto& entry : allocatedList) {
+ // we ignore any entries allocated for uncacheable
+ // accesses and simply ignore them when matching, in the
+ // cache we never check for matches when adding new
+ // uncacheable entries, and we do not want normal
+ // cacheable accesses being added to an WriteQueueEntry
+ // serving an uncacheable access
+ if (!entry->isUncacheable() && entry->blkAddr == blk_addr &&
+ entry->isSecure == is_secure) {
+ return entry;
+ }
+ }
+ return nullptr;
+ }
+
+ bool checkFunctional(PacketPtr pkt, Addr blk_addr)
+ {
+ pkt->pushLabel(label);
+ for (const auto& entry : allocatedList) {
+ if (entry->blkAddr == blk_addr && entry->checkFunctional(pkt)) {
+ pkt->popLabel();
+ return true;
+ }
+ }
+ pkt->popLabel();
+ return false;
+ }
+
+ /**
+ * Find any pending requests that overlap the given request.
+ * @param blk_addr Block address.
+ * @param is_secure True if the target memory space is secure.
+ * @return A pointer to the earliest matching WriteQueueEntry.
+ */
+ Entry* findPending(Addr blk_addr, bool is_secure) const
+ {
+ for (const auto& entry : readyList) {
+ if (entry->blkAddr == blk_addr && entry->isSecure == is_secure) {
+ return entry;
+ }
+ }
+ return nullptr;
+ }
+
+ /**
+ * Returns the WriteQueueEntry at the head of the readyList.
+ * @return The next request to service.
+ */
+ Entry* getNext() const
+ {
+ if (readyList.empty() || readyList.front()->readyTime > curTick()) {
+ return NULL;
+ }
+ return readyList.front();
+ }
+
+ Tick nextReadyTime() const
+ {
+ return readyList.empty() ? MaxTick : readyList.front()->readyTime;
+ }
+
+ /**
+ * Removes the given entry from the queue. This places the entry
+ * on the free list.
+ *
+ * @param entry
+ */
+ void deallocate(Entry *entry)
+ {
+ allocatedList.erase(entry->allocIter);
+ freeList.push_front(entry);
+ allocated--;
+ if (entry->inService) {
+ _numInService--;
+ } else {
+ readyList.erase(entry->readyIter);
+ }
+ entry->deallocate();
+ if (drainState() == DrainState::Draining && allocated == 0) {
+ // Notify the drain manager that we have completed
+ // draining if there are no other outstanding requests in
+ // this queue.
+ DPRINTF(Drain, "Queue now empty, signalling drained\n");
+ signalDrainDone();
+ }
+ }
+
+ DrainState drain() override
+ {
+ return allocated == 0 ? DrainState::Drained : DrainState::Draining;
+ }
+};
+
+#endif //__MEM_CACHE_QUEUE_HH__
diff --git a/src/mem/cache/queue_entry.hh b/src/mem/cache/queue_entry.hh
new file mode 100644
index 000000000..02daee01a
--- /dev/null
+++ b/src/mem/cache/queue_entry.hh
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder. You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Erik Hallnor
+ * Andreas Hansson
+ */
+
+/**
+ * @file
+ * Generic queue entry
+ */
+
+#ifndef __MEM_CACHE_QUEUE_ENTRY_HH__
+#define __MEM_CACHE_QUEUE_ENTRY_HH__
+
+#include "mem/packet.hh"
+
+class Cache;
+
+/**
+ * A queue entry base class, to be used by both the MSHRs and
+ * write-queue entries.
+ */
+class QueueEntry : public Packet::SenderState
+{
+
+ /**
+ * Consider the Queue a friend to avoid making everything public
+ */
+ template <class Entry>
+ friend class Queue;
+
+ protected:
+
+ /** Tick when ready to issue */
+ Tick readyTime;
+
+ /** True if the entry is uncacheable */
+ bool _isUncacheable;
+
+ public:
+
+ /** True if the entry has been sent downstream. */
+ bool inService;
+
+ /** Order number assigned to disambiguate writes and misses. */
+ Counter order;
+
+ /** Block aligned address. */
+ Addr blkAddr;
+
+ /** Block size of the cache. */
+ unsigned blkSize;
+
+ /** True if the entry targets the secure memory space. */
+ bool isSecure;
+
+ QueueEntry() : readyTime(0), _isUncacheable(false),
+ inService(false), order(0), blkAddr(0), blkSize(0),
+ isSecure(false)
+ {}
+
+ bool isUncacheable() const { return _isUncacheable; }
+
+ /**
+ * Send this queue entry as a downstream packet, with the exact
+ * behaviour depending on the specific entry type.
+ */
+ virtual bool sendPacket(Cache &cache) = 0;
+
+};
+
+#endif // __MEM_CACHE_QUEUE_ENTRY_HH__
diff --git a/src/mem/cache/write_queue.cc b/src/mem/cache/write_queue.cc
new file mode 100644
index 000000000..57489c6f0
--- /dev/null
+++ b/src/mem/cache/write_queue.cc
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder. You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2003-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Erik Hallnor
+ * Andreas Sandberg
+ * Andreas Hansson
+ */
+
+/** @file
+ * Definition of WriteQueue class functions.
+ */
+
+#include "mem/cache/write_queue.hh"
+
+using namespace std;
+
+WriteQueue::WriteQueue(const std::string &_label,
+ int num_entries, int reserve)
+ : Queue<WriteQueueEntry>(_label, num_entries, reserve)
+{}
+
+WriteQueueEntry *
+WriteQueue::allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
+ Tick when_ready, Counter order)
+{
+ assert(!freeList.empty());
+ WriteQueueEntry *entry = freeList.front();
+ assert(entry->getNumTargets() == 0);
+ freeList.pop_front();
+
+ entry->allocate(blk_addr, blk_size, pkt, when_ready, order);
+ entry->allocIter = allocatedList.insert(allocatedList.end(), entry);
+ entry->readyIter = addToReadyList(entry);
+
+ allocated += 1;
+ return entry;
+}
+
+void
+WriteQueue::markInService(WriteQueueEntry *entry)
+{
+ if (!entry->isUncacheable()) {
+ // a normal eviction, such as a writeback or a clean evict, no
+ // more to do as we are done from the perspective of this
+ // cache
+ entry->popTarget();
+ deallocate(entry);
+ } else {
+ // uncacheable write, and we will eventually receive a
+ // response
+ entry->markInService();
+ readyList.erase(entry->readyIter);
+ _numInService += 1;
+ }
+}
diff --git a/src/mem/cache/write_queue.hh b/src/mem/cache/write_queue.hh
new file mode 100644
index 000000000..006d70556
--- /dev/null
+++ b/src/mem/cache/write_queue.hh
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2015-2016 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder. You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Hansson
+ */
+
+/**
+ * @file Declaration of a queue structure to manage uncacheable write
+ * and writebacks.
+ */
+
+#ifndef __MEM_CACHE_WRITE_QUEUE_HH__
+#define __MEM_CACHE_WRITE_QUEUE_HH__
+
+#include <vector>
+
+#include "mem/cache/queue.hh"
+#include "mem/cache/write_queue_entry.hh"
+
+/**
+ * A write queue for all eviction packets, i.e. writebacks and clean
+ * evictions, as well as uncacheable writes.
+ */
+class WriteQueue : public Queue<WriteQueueEntry>
+{
+
+ public:
+
+ /**
+ * Create a write queue with a given number of entries.
+ * @param num_entries The number of entries in this queue.
+ * @param reserve The maximum number of entries needed to satisfy
+ * any access.
+ */
+ WriteQueue(const std::string &_label, int num_entries, int reserve);
+
+ /**
+ * Allocates a new WriteQueueEntry for the request and size. This
+ * places the request as the first target in the WriteQueueEntry.
+ *
+ * @param blk_addr The address of the block.
+ * @param blk_size The number of bytes to request.
+ * @param pkt The original write.
+ * @param when_ready When is the WriteQueueEntry be ready to act upon.
+ * @param order The logical order of this WriteQueueEntry
+ *
+ * @return The a pointer to the WriteQueueEntry allocated.
+ *
+ * @pre There are free entries.
+ */
+ WriteQueueEntry *allocate(Addr blk_addr, unsigned blk_size,
+ PacketPtr pkt, Tick when_ready, Counter order);
+
+ /**
+ * Mark the given entry as in service. This removes the entry from
+ * the readyList or deallocates the entry if it does not expect a
+ * response (writeback/eviction rather than an uncacheable write).
+ *
+ * @param entry The entry to mark in service.
+ */
+ void markInService(WriteQueueEntry *entry);
+};
+
+#endif //__MEM_CACHE_WRITE_QUEUE_HH__
diff --git a/src/mem/cache/write_queue_entry.cc b/src/mem/cache/write_queue_entry.cc
new file mode 100644
index 000000000..c55aba9c8
--- /dev/null
+++ b/src/mem/cache/write_queue_entry.cc
@@ -0,0 +1,185 @@
+/*
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder. You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * Copyright (c) 2010 Advanced Micro Devices, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Erik Hallnor
+ * Dave Greene
+ * Andreas Hansson
+ */
+
+/**
+ * @file
+ * Miss Status and Handling Register (WriteQueueEntry) definitions.
+ */
+
+#include "mem/cache/write_queue_entry.hh"
+
+#include <algorithm>
+#include <cassert>
+#include <string>
+#include <vector>
+
+#include "base/misc.hh"
+#include "base/types.hh"
+#include "debug/Cache.hh"
+#include "mem/cache/cache.hh"
+#include "sim/core.hh"
+
+using namespace std;
+
+inline void
+WriteQueueEntry::TargetList::add(PacketPtr pkt, Tick readyTime,
+ Counter order)
+{
+ emplace_back(pkt, readyTime, order);
+}
+
+bool
+WriteQueueEntry::TargetList::checkFunctional(PacketPtr pkt)
+{
+ for (auto& t : *this) {
+ if (pkt->checkFunctional(t.pkt)) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+void
+WriteQueueEntry::TargetList::print(std::ostream &os, int verbosity,
+ const std::string &prefix) const
+{
+ for (auto& t : *this) {
+ ccprintf(os, "%sFromCPU: ", prefix);
+ t.pkt->print(os, verbosity, "");
+ }
+}
+
+void
+WriteQueueEntry::allocate(Addr blk_addr, unsigned blk_size, PacketPtr target,
+ Tick when_ready, Counter _order)
+{
+ blkAddr = blk_addr;
+ blkSize = blk_size;
+ isSecure = target->isSecure();
+ readyTime = when_ready;
+ order = _order;
+ assert(target);
+ _isUncacheable = target->req->isUncacheable();
+ inService = false;
+
+ // we should never have more than a single target for cacheable
+ // writes (writebacks and clean evictions)
+ panic_if(!_isUncacheable && !targets.empty(),
+ "Write queue entry %#llx should never have more than one "
+ "cacheable target", blkAddr);
+ panic_if(!((target->isWrite() && _isUncacheable) ||
+ (target->isEviction() && !_isUncacheable)),
+ "Write queue entry %#llx should either be uncacheable write or "
+ "a cacheable eviction");
+
+ targets.add(target, when_ready, _order);
+}
+
+bool
+WriteQueueEntry::markInService()
+{
+ assert(!inService);
+ if (!isUncacheable()) {
+ // we just forwarded the request packet & don't expect a
+ // response, so get rid of it
+ assert(getNumTargets() == 1);
+ popTarget();
+ return true;
+ }
+
+ inService = true;
+
+ return false;
+}
+
+void
+WriteQueueEntry::deallocate()
+{
+ assert(targets.empty());
+ inService = false;
+}
+
+bool
+WriteQueueEntry::checkFunctional(PacketPtr pkt)
+{
+ // For printing, we treat the WriteQueueEntry as a whole as single
+ // entity. For other requests, we iterate over the individual
+ // targets since that's where the actual data lies.
+ if (pkt->isPrint()) {
+ pkt->checkFunctional(this, blkAddr, isSecure, blkSize, NULL);
+ return false;
+ } else {
+ return targets.checkFunctional(pkt);
+ }
+}
+
+bool
+WriteQueueEntry::sendPacket(Cache &cache)
+{
+ return cache.sendWriteQueuePacket(this);
+}
+
+void
+WriteQueueEntry::print(std::ostream &os, int verbosity,
+ const std::string &prefix) const
+{
+ ccprintf(os, "%s[%#llx:%#llx](%s) %s %s %s state: %s %s %s %s %s\n",
+ prefix, blkAddr, blkAddr + blkSize - 1,
+ isSecure ? "s" : "ns",
+ _isUncacheable ? "Unc" : "",
+ inService ? "InSvc" : "");
+
+ ccprintf(os, "%s Targets:\n", prefix);
+ targets.print(os, verbosity, prefix + " ");
+}
+
+std::string
+WriteQueueEntry::print() const
+{
+ ostringstream str;
+ print(str);
+ return str.str();
+}
diff --git a/src/mem/cache/write_queue_entry.hh b/src/mem/cache/write_queue_entry.hh
new file mode 100644
index 000000000..7e3422431
--- /dev/null
+++ b/src/mem/cache/write_queue_entry.hh
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder. You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2002-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Erik Hallnor
+ * Andreas Hansson
+ */
+
+/**
+ * @file
+ * Write queue entry
+ */
+
+#ifndef __MEM_CACHE_WRITE_QUEUE_ENTRY_HH__
+#define __MEM_CACHE_WRITE_QUEUE_ENTRY_HH__
+
+#include <list>
+
+#include "base/printable.hh"
+#include "mem/cache/queue_entry.hh"
+
+class Cache;
+
+/**
+ * Write queue entry
+ */
+class WriteQueueEntry : public QueueEntry, public Printable
+{
+
+ /**
+ * Consider the queues friends to avoid making everything public.
+ */
+ template<typename Entry>
+ friend class Queue;
+ friend class WriteQueue;
+
+ public:
+
+ class Target {
+ public:
+
+ const Tick recvTime; //!< Time when request was received (for stats)
+ const Tick readyTime; //!< Time when request is ready to be serviced
+ const Counter order; //!< Global order (for memory consistency mgmt)
+ const PacketPtr pkt; //!< Pending request packet.
+
+ Target(PacketPtr _pkt, Tick _readyTime, Counter _order)
+ : recvTime(curTick()), readyTime(_readyTime), order(_order),
+ pkt(_pkt)
+ {}
+ };
+
+ class TargetList : public std::list<Target> {
+
+ public:
+
+ TargetList() {}
+ void add(PacketPtr pkt, Tick readyTime, Counter order);
+ bool checkFunctional(PacketPtr pkt);
+ void print(std::ostream &os, int verbosity,
+ const std::string &prefix) const;
+ };
+
+ /** A list of write queue entriess. */
+ typedef std::list<WriteQueueEntry *> List;
+ /** WriteQueueEntry list iterator. */
+ typedef List::iterator Iterator;
+
+ bool sendPacket(Cache &cache);
+
+ private:
+
+ /**
+ * Pointer to this entry on the ready list.
+ * @sa MissQueue, WriteQueue::readyList
+ */
+ Iterator readyIter;
+
+ /**
+ * Pointer to this entry on the allocated list.
+ * @sa MissQueue, WriteQueue::allocatedList
+ */
+ Iterator allocIter;
+
+ /** List of all requests that match the address */
+ TargetList targets;
+
+ public:
+
+ /** A simple constructor. */
+ WriteQueueEntry() {}
+
+ /**
+ * Allocate a miss to this entry.
+ * @param blk_addr The address of the block.
+ * @param blk_size The number of bytes to request.
+ * @param pkt The original write.
+ * @param when_ready When should the write be sent out.
+ * @param _order The logical order of this write.
+ */
+ void allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
+ Tick when_ready, Counter _order);
+
+ bool markInService();
+
+ /**
+ * Mark this entry as free.
+ */
+ void deallocate();
+
+ /**
+ * Returns the current number of allocated targets.
+ * @return The current number of allocated targets.
+ */
+ int getNumTargets() const
+ { return targets.size(); }
+
+ /**
+ * Returns true if there are targets left.
+ * @return true if there are targets
+ */
+ bool hasTargets() const { return !targets.empty(); }
+
+ /**
+ * Returns a reference to the first target.
+ * @return A pointer to the first target.
+ */
+ Target *getTarget()
+ {
+ assert(hasTargets());
+ return &targets.front();
+ }
+
+ /**
+ * Pop first target.
+ */
+ void popTarget()
+ {
+ targets.pop_front();
+ }
+
+ bool checkFunctional(PacketPtr pkt);
+
+ /**
+ * Prints the contents of this MSHR for debugging.
+ */
+ void print(std::ostream &os,
+ int verbosity = 0,
+ const std::string &prefix = "") const;
+ /**
+ * A no-args wrapper of print(std::ostream...) meant to be
+ * invoked from DPRINTFs avoiding string overheads in fast mode
+ *
+ * @return string with mshr fields
+ */
+ std::string print() const;
+};
+
+#endif // __MEM_CACHE_WRITE_QUEUE_ENTRY_HH__