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-rw-r--r--src/mem/cache/base_cache.hh26
-rw-r--r--src/mem/cache/cache_impl.hh195
-rw-r--r--src/mem/cache/miss/mshr.cc18
-rw-r--r--src/mem/cache/miss/mshr.hh2
-rw-r--r--src/mem/packet.hh3
5 files changed, 122 insertions, 122 deletions
diff --git a/src/mem/cache/base_cache.hh b/src/mem/cache/base_cache.hh
index 46414974b..719ab0245 100644
--- a/src/mem/cache/base_cache.hh
+++ b/src/mem/cache/base_cache.hh
@@ -410,28 +410,28 @@ class BaseCache : public MemObject
MSHR *allocateMissBuffer(PacketPtr pkt, Tick time, bool requestBus)
{
+ assert(!pkt->req->isUncacheable());
return allocateBufferInternal(&mshrQueue,
blockAlign(pkt->getAddr()), blkSize,
pkt, time, requestBus);
}
- MSHR *allocateBuffer(PacketPtr pkt, Tick time, bool requestBus)
+ MSHR *allocateWriteBuffer(PacketPtr pkt, Tick time, bool requestBus)
{
- MSHRQueue *mq = NULL;
-
- if (pkt->isWrite() && !pkt->isRead()) {
- /**
- * @todo Add write merging here.
- */
- mq = &writeBuffer;
- } else {
- mq = &mshrQueue;
- }
-
- return allocateBufferInternal(mq, pkt->getAddr(), pkt->getSize(),
+ assert(pkt->isWrite() && !pkt->isRead());
+ return allocateBufferInternal(&writeBuffer,
+ pkt->getAddr(), pkt->getSize(),
pkt, time, requestBus);
}
+ MSHR *allocateUncachedReadBuffer(PacketPtr pkt, Tick time, bool requestBus)
+ {
+ assert(pkt->req->isUncacheable());
+ assert(pkt->isRead());
+ return allocateBufferInternal(&mshrQueue,
+ pkt->getAddr(), pkt->getSize(),
+ pkt, time, requestBus);
+ }
/**
* Returns true if the cache is blocked for accesses.
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index c069d8ba9..b78360d4a 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -369,7 +369,12 @@ Cache<TagStore>::timingAccess(PacketPtr pkt)
}
if (pkt->req->isUncacheable()) {
- allocateBuffer(pkt, time, true);
+ // writes go in write buffer, reads use MSHR
+ if (pkt->isWrite() && !pkt->isRead()) {
+ allocateWriteBuffer(pkt, time, true);
+ } else {
+ allocateUncachedReadBuffer(pkt, time, true);
+ }
assert(pkt->needsResponse()); // else we should delete it here??
return true;
}
@@ -417,7 +422,7 @@ Cache<TagStore>::timingAccess(PacketPtr pkt)
// copy writebacks to write buffer
while (!writebacks.empty()) {
PacketPtr wbPkt = writebacks.front();
- allocateBuffer(wbPkt, time, true);
+ allocateWriteBuffer(wbPkt, time, true);
writebacks.pop_front();
}
#endif
@@ -458,7 +463,11 @@ Cache<TagStore>::timingAccess(PacketPtr pkt)
// always mark as cache fill for now... if we implement
// no-write-allocate or bypass accesses this will have to
// be changed.
- allocateMissBuffer(pkt, time, true);
+ if (pkt->cmd == MemCmd::Writeback) {
+ allocateWriteBuffer(pkt, time, true);
+ } else {
+ allocateMissBuffer(pkt, time, true);
+ }
}
}
@@ -492,6 +501,10 @@ Cache<TagStore>::getBusPacket(PacketPtr cpu_pkt, BlkType *blk,
assert(cpu_pkt->needsResponse());
MemCmd cmd;
+ // @TODO make useUpgrades a parameter.
+ // Note that ownership protocols require upgrade, otherwise a
+ // write miss on a shared owned block will generate a ReadExcl,
+ // which will clobber the owned copy.
const bool useUpgrades = true;
if (blkValid && useUpgrades) {
// only reason to be here is that blk is shared
@@ -649,62 +662,6 @@ Cache<TagStore>::functionalAccess(PacketPtr pkt,
template<class TagStore>
-bool
-Cache<TagStore>::satisfyMSHR(MSHR *mshr, PacketPtr pkt,
- BlkType *blk)
-{
- // respond to MSHR targets, if any
-
- // First offset for critical word first calculations
- int initial_offset = 0;
-
- if (mshr->hasTargets()) {
- initial_offset = mshr->getTarget()->pkt->getOffset(blkSize);
- }
-
- while (mshr->hasTargets()) {
- MSHR::Target *target = mshr->getTarget();
-
- if (target->isCpuSide()) {
- satisfyCpuSideRequest(target->pkt, blk);
- // How many bytes pass the first request is this one
- int transfer_offset =
- target->pkt->getOffset(blkSize) - initial_offset;
- if (transfer_offset < 0) {
- transfer_offset += blkSize;
- }
-
- // If critical word (no offset) return first word time
- Tick completion_time = tags->getHitLatency() +
- transfer_offset ? pkt->finishTime : pkt->firstWordTime;
-
- if (!target->pkt->req->isUncacheable()) {
- missLatency[target->pkt->cmdToIndex()][0/*pkt->req->getThreadNum()*/] +=
- completion_time - target->recvTime;
- }
- target->pkt->makeTimingResponse();
- cpuSidePort->respond(target->pkt, completion_time);
- } else {
- // response to snoop request
- DPRINTF(Cache, "processing deferred snoop...\n");
- handleSnoop(target->pkt, blk, true, true);
- }
-
- mshr->popTarget();
- }
-
- if (mshr->promoteDeferredTargets()) {
- MSHRQueue *mq = mshr->queue;
- mq->markPending(mshr);
- requestMemSideBus((RequestCause)mq->index, pkt->finishTime);
- return false;
- }
-
- return true;
-}
-
-
-template<class TagStore>
void
Cache<TagStore>::handleResponse(PacketPtr pkt)
{
@@ -730,68 +687,105 @@ Cache<TagStore>::handleResponse(PacketPtr pkt)
noTargetMSHR = NULL;
}
- // Can we deallocate MSHR when done?
- bool deallocate = false;
-
// Initial target is used just for stats
MSHR::Target *initial_tgt = mshr->getTarget();
+ BlkType *blk = tags->findBlock(pkt->getAddr());
int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
Tick miss_latency = curTick - initial_tgt->recvTime;
+ PacketList writebacks;
- if (mshr->isCacheFill) {
+ if (pkt->req->isUncacheable()) {
+ mshr_uncacheable_lat[stats_cmd_idx][0/*pkt->req->getThreadNum()*/] +=
+ miss_latency;
+ } else {
mshr_miss_latency[stats_cmd_idx][0/*pkt->req->getThreadNum()*/] +=
miss_latency;
+ }
+
+ if (mshr->isCacheFill) {
DPRINTF(Cache, "Block for addr %x being updated in Cache\n",
pkt->getAddr());
- BlkType *blk = tags->findBlock(pkt->getAddr());
// give mshr a chance to do some dirty work
mshr->handleFill(pkt, blk);
- PacketList writebacks;
blk = handleFill(pkt, blk, writebacks);
- deallocate = satisfyMSHR(mshr, pkt, blk);
- // copy writebacks to write buffer
- while (!writebacks.empty()) {
- PacketPtr wbPkt = writebacks.front();
- allocateBuffer(wbPkt, time, true);
- writebacks.pop_front();
- }
- // if we used temp block, clear it out
- if (blk == tempBlock) {
- if (blk->isDirty()) {
- allocateBuffer(writebackBlk(blk), time, true);
- }
- tags->invalidateBlk(blk);
- }
- } else {
- if (pkt->req->isUncacheable()) {
- mshr_uncacheable_lat[stats_cmd_idx][0/*pkt->req->getThreadNum()*/] +=
- miss_latency;
- }
+ assert(blk != NULL);
+ }
- while (mshr->hasTargets()) {
- MSHR::Target *target = mshr->getTarget();
- assert(target->isCpuSide());
- mshr->popTarget();
- if (pkt->isRead()) {
- target->pkt->setData(pkt->getPtr<uint8_t>());
+ // First offset for critical word first calculations
+ int initial_offset = 0;
+
+ if (mshr->hasTargets()) {
+ initial_offset = mshr->getTarget()->pkt->getOffset(blkSize);
+ }
+
+ while (mshr->hasTargets()) {
+ MSHR::Target *target = mshr->getTarget();
+
+ if (target->isCpuSide()) {
+ Tick completion_time;
+ if (blk != NULL) {
+ satisfyCpuSideRequest(target->pkt, blk);
+ // How many bytes pass the first request is this one
+ int transfer_offset =
+ target->pkt->getOffset(blkSize) - initial_offset;
+ if (transfer_offset < 0) {
+ transfer_offset += blkSize;
+ }
+
+ // If critical word (no offset) return first word time
+ completion_time = tags->getHitLatency() +
+ transfer_offset ? pkt->finishTime : pkt->firstWordTime;
+
+ if (!target->pkt->req->isUncacheable()) {
+ missLatency[target->pkt->cmdToIndex()][0/*pkt->req->getThreadNum()*/] +=
+ completion_time - target->recvTime;
+ }
+ } else {
+ // not a cache fill, just forwarding response
+ completion_time = tags->getHitLatency() + pkt->finishTime;
+ if (pkt->isRead()) {
+ target->pkt->setData(pkt->getPtr<uint8_t>());
+ }
}
target->pkt->makeTimingResponse();
- cpuSidePort->respond(target->pkt, time);
+ cpuSidePort->respond(target->pkt, completion_time);
+ } else {
+ // response to snoop request
+ DPRINTF(Cache, "processing deferred snoop...\n");
+ handleSnoop(target->pkt, blk, true, true);
}
- assert(!mshr->hasTargets());
- deallocate = true;
- }
- delete pkt;
+ mshr->popTarget();
+ }
- if (deallocate) {
+ if (mshr->promoteDeferredTargets()) {
+ MSHRQueue *mq = mshr->queue;
+ mq->markPending(mshr);
+ requestMemSideBus((RequestCause)mq->index, pkt->finishTime);
+ } else {
mq->deallocate(mshr);
if (wasFull && !mq->isFull()) {
clearBlocked((BlockedCause)mq->index);
}
}
+
+ // copy writebacks to write buffer
+ while (!writebacks.empty()) {
+ PacketPtr wbPkt = writebacks.front();
+ allocateWriteBuffer(wbPkt, time, true);
+ writebacks.pop_front();
+ }
+ // if we used temp block, clear it out
+ if (blk == tempBlock) {
+ if (blk->isDirty()) {
+ allocateWriteBuffer(writebackBlk(blk), time, true);
+ }
+ tags->invalidateBlk(blk);
+ }
+
+ delete pkt;
}
@@ -933,6 +927,9 @@ Cache<TagStore>::handleSnoop(PacketPtr pkt, BlkType *blk,
if (is_timing) {
Packet *snoopPkt = new Packet(pkt, true); // clear flags
snoopPkt->setExpressSnoop();
+ if (is_deferred) {
+ snoopPkt->setDeferredSnoop();
+ }
snoopPkt->senderState = new ForwardResponseRecord(pkt, this);
cpuSidePort->sendTiming(snoopPkt);
if (snoopPkt->memInhibitAsserted()) {
@@ -1020,12 +1017,11 @@ Cache<TagStore>::snoopTiming(PacketPtr pkt)
MSHR *mshr = mshrQueue.findMatch(blk_addr);
// better not be snooping a request that conflicts with something
// we have outstanding...
- if (mshr && mshr->inService) {
+ if (mshr && mshr->handleSnoop(pkt, order++)) {
DPRINTF(Cache, "Deferring snoop on in-service MSHR to blk %x\n",
blk_addr);
- mshr->allocateSnoopTarget(pkt, curTick, order++);
if (mshr->getNumTargets() > numTarget)
- warn("allocating bonus target for snoop"); //handle later
+ warn("allocating bonus target for snoop"); //handle later
return;
}
@@ -1226,6 +1222,7 @@ template<class TagStore>
bool
Cache<TagStore>::CpuSidePort::recvTiming(PacketPtr pkt)
{
+ // illegal to block responses... can lead to deadlock
if (pkt->isRequest() && blocked) {
DPRINTF(Cache,"Scheduling a retry while blocked\n");
mustSendRetry = true;
diff --git a/src/mem/cache/miss/mshr.cc b/src/mem/cache/miss/mshr.cc
index 5d5e63f90..7ba3789fe 100644
--- a/src/mem/cache/miss/mshr.cc
+++ b/src/mem/cache/miss/mshr.cc
@@ -119,25 +119,23 @@ MSHR::allocateTarget(PacketPtr target, Tick whenReady, Counter _order)
++ntargets;
}
-void
-MSHR::allocateSnoopTarget(PacketPtr pkt, Tick whenReady, Counter _order)
+bool
+MSHR::handleSnoop(PacketPtr pkt, Counter _order)
{
- assert(inService); // don't bother to call otherwise
+ if (!inService || (pkt->isExpressSnoop() && !pkt->isDeferredSnoop())) {
+ return false;
+ }
if (pendingInvalidate) {
// a prior snoop has already appended an invalidation, so
// logically we don't have the block anymore...
- return;
+ return true;
}
- DPRINTF(Cache, "deferred snoop on %x: %s %s\n", addr,
- needsExclusive ? "needsExclusive" : "",
- pkt->needsExclusive() ? "pkt->needsExclusive()" : "");
-
if (needsExclusive || pkt->needsExclusive()) {
// actual target device (typ. PhysicalMemory) will delete the
// packet on reception, so we need to save a copy here
- targets.push_back(Target(new Packet(pkt), whenReady, _order, false));
+ targets.push_back(Target(new Packet(pkt), curTick, _order, false));
++ntargets;
if (needsExclusive) {
@@ -157,6 +155,8 @@ MSHR::allocateSnoopTarget(PacketPtr pkt, Tick whenReady, Counter _order)
pendingShared = true;
pkt->assertShared();
}
+
+ return true;
}
diff --git a/src/mem/cache/miss/mshr.hh b/src/mem/cache/miss/mshr.hh
index a27f465aa..9c6a8cf33 100644
--- a/src/mem/cache/miss/mshr.hh
+++ b/src/mem/cache/miss/mshr.hh
@@ -162,7 +162,7 @@ public:
* @param target The target.
*/
void allocateTarget(PacketPtr target, Tick when, Counter order);
- void allocateSnoopTarget(PacketPtr target, Tick when, Counter order);
+ bool handleSnoop(PacketPtr target, Counter order);
/** A simple constructor. */
MSHR();
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index 036bd3fd7..8063c7ae7 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -257,6 +257,7 @@ class Packet : public FastAlloc
Shared,
// Special control flags
ExpressSnoop,
+ DeferredSnoop,
NUM_PACKET_FLAGS
};
@@ -322,6 +323,8 @@ class Packet : public FastAlloc
// Special control flags
void setExpressSnoop() { flags[ExpressSnoop] = true; }
bool isExpressSnoop() { return flags[ExpressSnoop]; }
+ void setDeferredSnoop() { flags[DeferredSnoop] = true; }
+ bool isDeferredSnoop() { return flags[DeferredSnoop]; }
// Network error conditions... encapsulate them as methods since
// their encoding keeps changing (from result field to command
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-27 07:12:42 +0000