summaryrefslogtreecommitdiff
path: root/src/mem/cache
diff options
context:
space:
mode:
authorSteve Reinhardt <stever@gmail.com>2008-01-02 15:18:33 -0800
committerSteve Reinhardt <stever@gmail.com>2008-01-02 15:18:33 -0800
commitbf9b3821bda5f534a44b176c0ed738a17cb9b80a (patch)
tree8de3cfcbb3a27a705f2f497823da34040d498066 /src/mem/cache
parent538da9e24d5797c6931c0214036c0156a1144c0e (diff)
downloadgem5-bf9b3821bda5f534a44b176c0ed738a17cb9b80a.tar.xz
Mark cache-to-cache MSHRs as downstreamPending when necessary.
Don't mark upstream MSHR as pending if downstream MSHR is already in service. --HG-- extra : convert_revision : e1c135ff00217291db58ce8a06ccde34c403d37f
Diffstat (limited to 'src/mem/cache')
-rw-r--r--src/mem/cache/miss/mshr.cc44
-rw-r--r--src/mem/cache/miss/mshr.hh12
2 files changed, 41 insertions, 15 deletions
diff --git a/src/mem/cache/miss/mshr.cc b/src/mem/cache/miss/mshr.cc
index 88d2acea0..d711ca537 100644
--- a/src/mem/cache/miss/mshr.cc
+++ b/src/mem/cache/miss/mshr.cc
@@ -64,7 +64,7 @@ MSHR::TargetList::TargetList()
inline void
MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
- Counter order, bool cpuSide)
+ Counter order, bool cpuSide, bool markPending)
{
if (cpuSide) {
if (pkt->needsExclusive()) {
@@ -74,7 +74,9 @@ MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
if (pkt->cmd == MemCmd::UpgradeReq) {
hasUpgrade = true;
}
+ }
+ if (markPending) {
MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
if (mshr != NULL) {
assert(!mshr->downstreamPending);
@@ -82,7 +84,7 @@ MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
}
}
- push_back(Target(pkt, readyTime, order, cpuSide));
+ push_back(Target(pkt, readyTime, order, cpuSide, markPending));
}
@@ -109,10 +111,11 @@ MSHR::TargetList::clearDownstreamPending()
{
Iterator end_i = end();
for (Iterator i = begin(); i != end_i; ++i) {
- MSHR *mshr = dynamic_cast<MSHR*>(i->pkt->senderState);
- if (mshr != NULL) {
- assert(mshr->downstreamPending);
- mshr->downstreamPending = false;
+ if (i->markedPending) {
+ MSHR *mshr = dynamic_cast<MSHR*>(i->pkt->senderState);
+ if (mshr != NULL) {
+ mshr->clearDownstreamPending();
+ }
}
}
}
@@ -162,7 +165,7 @@ MSHR::allocate(Addr _addr, int _size, PacketPtr target,
// Don't know of a case where we would allocate a new MSHR for a
// snoop (mem-side request), so set cpuSide to true here.
assert(targets->isReset());
- targets->add(target, whenReady, _order, true);
+ targets->add(target, whenReady, _order, true, true);
assert(deferredTargets->isReset());
pendingInvalidate = false;
pendingShared = false;
@@ -170,6 +173,16 @@ MSHR::allocate(Addr _addr, int _size, PacketPtr target,
}
+void
+MSHR::clearDownstreamPending()
+{
+ assert(downstreamPending);
+ downstreamPending = false;
+ // recursively clear flag on any MSHRs we will be forwarding
+ // responses to
+ targets->clearDownstreamPending();
+}
+
bool
MSHR::markInService()
{
@@ -221,11 +234,13 @@ MSHR::allocateTarget(PacketPtr pkt, Tick whenReady, Counter _order)
(!deferredTargets->empty() || pendingInvalidate ||
(!targets->needsExclusive && pkt->needsExclusive()))) {
// need to put on deferred list
- deferredTargets->add(pkt, whenReady, _order, true);
+ deferredTargets->add(pkt, whenReady, _order, true, true);
} else {
- // no request outstanding, or still OK to append to
- // outstanding request
- targets->add(pkt, whenReady, _order, true);
+ // No request outstanding, or still OK to append to
+ // outstanding request: append to regular target list. Only
+ // mark pending if current request hasn't been issued yet
+ // (isn't in service).
+ targets->add(pkt, whenReady, _order, true, !inService);
}
++ntargets;
@@ -276,7 +291,8 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order)
// actual target device (typ. PhysicalMemory) will delete the
// packet on reception, so we need to save a copy here
PacketPtr cp_pkt = new Packet(pkt, true);
- targets->add(cp_pkt, curTick, _order, false);
+ targets->add(cp_pkt, curTick, _order, false,
+ downstreamPending && targets->needsExclusive);
++ntargets;
if (targets->needsExclusive) {
@@ -355,6 +371,10 @@ MSHR::handleFill(Packet *pkt, CacheBlk *blk)
// the regular target list.
assert(!targets->needsExclusive);
targets->needsExclusive = true;
+ // if any of the deferred targets were upper-level cache
+ // requests marked downstreamPending, need to clear that
+ assert(!downstreamPending); // not pending here anymore
+ deferredTargets->clearDownstreamPending();
// this clears out deferredTargets too
targets->splice(targets->end(), *deferredTargets);
deferredTargets->resetFlags();
diff --git a/src/mem/cache/miss/mshr.hh b/src/mem/cache/miss/mshr.hh
index 0bc3c4480..fdb0485cb 100644
--- a/src/mem/cache/miss/mshr.hh
+++ b/src/mem/cache/miss/mshr.hh
@@ -60,12 +60,15 @@ class MSHR : public Packet::SenderState, public Printable
Counter order; //!< Global order (for memory consistency mgmt)
PacketPtr pkt; //!< Pending request packet.
bool cpuSide; //!< Did request come from cpu side or mem side?
+ bool markedPending; //!< Did we mark upstream MSHR
+ //!< as downstreamPending?
bool isCpuSide() const { return cpuSide; }
- Target(PacketPtr _pkt, Tick _readyTime, Counter _order, bool _cpuSide)
+ Target(PacketPtr _pkt, Tick _readyTime, Counter _order,
+ bool _cpuSide, bool _markedPending)
: recvTime(curTick), readyTime(_readyTime), order(_order),
- pkt(_pkt), cpuSide(_cpuSide)
+ pkt(_pkt), cpuSide(_cpuSide), markedPending(_markedPending)
{}
};
@@ -81,7 +84,8 @@ class MSHR : public Packet::SenderState, public Printable
TargetList();
void resetFlags() { needsExclusive = hasUpgrade = false; }
bool isReset() { return !needsExclusive && !hasUpgrade; }
- void add(PacketPtr pkt, Tick readyTime, Counter order, bool cpuSide);
+ void add(PacketPtr pkt, Tick readyTime, Counter order,
+ bool cpuSide, bool markPending);
void replaceUpgrades();
void clearDownstreamPending();
bool checkFunctional(PacketPtr pkt);
@@ -173,6 +177,8 @@ public:
bool markInService();
+ void clearDownstreamPending();
+
/**
* Mark this MSHR as free.
*/