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authorSteve Reinhardt <stever@eecs.umich.edu>2007-07-23 22:28:40 -0700
committerSteve Reinhardt <stever@eecs.umich.edu>2007-07-23 22:28:40 -0700
commit1f9ea6e122f6a39d936aec2f8f5ce72d267799a8 (patch)
tree973cc374a80ae441a3ef6c7888342244a37d394f
parent97f7ee2e507733eb9dd1802c16900fd14ae6b7f3 (diff)
downloadgem5-1f9ea6e122f6a39d936aec2f8f5ce72d267799a8.tar.xz
A couple more minor bug fixes for multilevel coherence.
--HG-- extra : convert_revision : 370f9e34911157765be6fd49e826fa1af589b466
-rw-r--r--src/mem/cache/cache_impl.hh21
-rw-r--r--src/mem/cache/miss/mshr.cc10
2 files changed, 22 insertions, 9 deletions
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index efd7f4588..412d10599 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -148,7 +148,13 @@ void
Cache<TagStore>::satisfyCpuSideRequest(PacketPtr pkt, BlkType *blk)
{
assert(blk);
- assert(pkt->needsExclusive() ? blk->isWritable() : blk->isValid());
+ // Occasionally this is not true... if we are a lower-level cache
+ // satisfying a string of Read and ReadEx requests from
+ // upper-level caches, a Read will mark the block as shared but we
+ // can satisfy a following ReadEx anyway since we can rely on the
+ // Read requester(s) to have buffered the ReadEx snoop and to
+ // invalidate their blocks after receiving them.
+ // assert(pkt->needsExclusive() ? blk->isWritable() : blk->isValid());
assert(pkt->getOffset(blkSize) + pkt->getSize() <= blkSize);
// Check RMW operations first since both isRead() and
@@ -727,7 +733,7 @@ Cache<TagStore>::handleResponse(PacketPtr pkt)
Tick completion_time;
if (blk != NULL) {
satisfyCpuSideRequest(target->pkt, blk);
- // How many bytes pass the first request is this one
+ // How many bytes past the first request is this one
int transfer_offset =
target->pkt->getOffset(blkSize) - initial_offset;
if (transfer_offset < 0) {
@@ -738,10 +744,9 @@ Cache<TagStore>::handleResponse(PacketPtr pkt)
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;
- }
+ assert(!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;
@@ -1004,7 +1009,9 @@ template<class TagStore>
void
Cache<TagStore>::snoopTiming(PacketPtr pkt)
{
- if (pkt->req->isUncacheable()) {
+ // Note that some deferred snoops don't have requests, since the
+ // original access may have already completed
+ if (pkt->req && pkt->req->isUncacheable()) {
//Can't get a hit on an uncacheable address
//Revisit this for multi level coherence
return;
diff --git a/src/mem/cache/miss/mshr.cc b/src/mem/cache/miss/mshr.cc
index 9b05aea3f..7f216ad39 100644
--- a/src/mem/cache/miss/mshr.cc
+++ b/src/mem/cache/miss/mshr.cc
@@ -208,7 +208,7 @@ MSHR::allocateTarget(PacketPtr pkt, Tick whenReady, Counter _order)
bool
MSHR::handleSnoop(PacketPtr pkt, Counter _order)
{
- if (!inService || downstreamPending) {
+ if (!inService || (pkt->isExpressSnoop() && downstreamPending)) {
// Request has not been issued yet, or it's been issued
// locally but is buffered unissued at some downstream cache
// which is forwarding us this snoop. Either way, the packet
@@ -249,13 +249,19 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order)
if (targets->needsExclusive || pkt->needsExclusive()) {
// actual target device (typ. PhysicalMemory) will delete the
// packet on reception, so we need to save a copy here
- targets->add(new Packet(pkt), curTick, _order, false);
+ PacketPtr cp_pkt = new Packet(pkt);
+ targets->add(cp_pkt, curTick, _order, false);
++ntargets;
if (targets->needsExclusive) {
// We're awaiting an exclusive copy, so ownership is pending.
// It's up to us to respond once the data arrives.
pkt->assertMemInhibit();
+ } else {
+ // Someone else may respond before we get around to
+ // processing this snoop, which means the copied request
+ // pointer will no longer be valid
+ cp_pkt->req = NULL;
}
if (pkt->needsExclusive()) {