Nikos Nikoleris has submitted this change and it was merged. (
https://gem5-review.googlesource.com/11016 )
Change subject: mem-cache: Fix promoting of targets that need writable
......................................................................
mem-cache: Fix promoting of targets that need writable
There are cases where a request which does not need a writable copy
gets an response upgraded reponse and fills in a writable copy. When
this happens, we promote deferred MSHR targets that were deferred
because they needed a writable copy to service them immediately.
Previously, we would uncoditionally promote deferred targets. Since
the deferred targets might contain a cache invalidation operation, we
have to make sure that any targets following the cache invalidation is
not promoted.
Change-Id: I1f7b28f7d35f84329e065c8f63117db21852365a
Reviewed-on: https://gem5-review.googlesource.com/11016
Reviewed-by: Daniel Carvalho <[email protected]>
Reviewed-by: Jason Lowe-Power <[email protected]>
Maintainer: Jason Lowe-Power <[email protected]>
---
M src/mem/cache/mshr.cc
M src/mem/cache/mshr.hh
2 files changed, 21 insertions(+), 4 deletions(-)
Approvals:
Jason Lowe-Power: Looks good to me, approved; Looks good to me, approved
Daniel Carvalho: Looks good to me, approved
diff --git a/src/mem/cache/mshr.cc b/src/mem/cache/mshr.cc
index d6208dd..8ef8a2c 100644
--- a/src/mem/cache/mshr.cc
+++ b/src/mem/cache/mshr.cc
@@ -566,10 +566,20 @@
// 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();
+
+ auto last_it = std::find_if(
+ deferredTargets.begin(), deferredTargets.end(),
+ [](MSHR::Target &t) {
+ assert(t.source == Target::FromCPU);
+ return t.pkt->req->isCacheInvalidate();
+ });
+ deferredTargets.clearDownstreamPending(deferredTargets.begin(),
+ last_it);
+ targets.splice(targets.end(), deferredTargets,
+ deferredTargets.begin(), last_it);
+ // We need to update the flags for the target lists after the
+ // modifications
+ deferredTargets.populateFlags();
}
}
diff --git a/src/mem/cache/mshr.hh b/src/mem/cache/mshr.hh
index f93d3c0..71c2da2 100644
--- a/src/mem/cache/mshr.hh
+++ b/src/mem/cache/mshr.hh
@@ -385,6 +385,13 @@
bool promoteDeferredTargets();
+ /**
+ * Promotes deferred targets that do not require writable
+ *
+ * Requests in the deferred target list are moved to the target
+ * list up until the first target that is a cache maintenance
+ * operation or needs a writable copy of the block
+ */
void promoteWritable();
bool checkFunctional(PacketPtr pkt);
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I1f7b28f7d35f84329e065c8f63117db21852365a
Gerrit-Change-Number: 11016
Gerrit-PatchSet: 3
Gerrit-Owner: Nikos Nikoleris <[email protected]>
Gerrit-Reviewer: Daniel Carvalho <[email protected]>
Gerrit-Reviewer: Jason Lowe-Power <[email protected]>
Gerrit-Reviewer: Nikos Nikoleris <[email protected]>
Gerrit-MessageType: merged
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