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mem-cache: Promote deferred targets on cache clean responses

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While a cache clean operation is pending, all requests to the
corresponding block get deferred. When the response of a cache clean
operation is received, if the block is present and the response is not
invalidating, we can service all deferred targets that didn't require
writable. This change implements this functionality.

Change-Id: Ief47e74d07749a6a9736ab450eb46eefa53464a2
Reviewed-on: https://gem5-review.googlesource.com/11018
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
This commit is contained in:
Nikos Nikoleris
2018-03-18 22:07:30 +00:00
parent f4015a2c62
commit fe330fdd35
2 changed files with 10 additions and 6 deletions
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8
src/mem/cache/base.cc vendored
View File

@@ -491,6 +491,12 @@ BaseCache::recvTimingResp(PacketPtr pkt)
// The block was marked not readable while there was a pending
// cache maintenance operation, restore its flag.
blk->status |= BlkReadable;
// This was a cache clean operation (without invalidate)
// and we have a copy of the block already. Since there
// is no invalidation, we can promote targets that don't
// require a writable copy
mshr->promoteReadable();
}
if (blk && blk->isWritable() && !pkt->req->isCacheInvalidate()) {
@@ -887,6 +893,8 @@ BaseCache::satisfyRequest(PacketPtr pkt, CacheBlk *blk, bool, bool)
pkt->setCacheResponding();
blk->status &= ~BlkDirty;
}
} else if (pkt->isClean()) {
blk->status &= ~BlkDirty;
} else {
assert(pkt->isInvalidate());
invalidateBlock(blk);

8
src/mem/cache/cache.cc vendored
View File

@@ -674,8 +674,6 @@ Cache::serviceMSHRTargets(MSHR *mshr, const PacketPtr pkt, CacheBlk *blk,
const int initial_offset = initial_tgt->pkt->getOffset(blkSize);
const bool is_error = pkt->isError();
bool is_fill = !mshr->isForward &&
(pkt->isRead() || pkt->cmd == MemCmd::UpgradeResp);
// allow invalidation responses originating from write-line
// requests to be discarded
bool is_invalidate = pkt->isInvalidate();
@@ -716,13 +714,11 @@ Cache::serviceMSHRTargets(MSHR *mshr, const PacketPtr pkt, CacheBlk *blk,
targets.allocOnFill);
assert(blk);
// treat as a fill, and discard the invalidation
// response
is_fill = true;
// discard the invalidation response
is_invalidate = false;
}
if (is_fill) {
if (blk && blk->isValid() && !mshr->isForward) {
satisfyRequest(tgt_pkt, blk, true, mshr->hasPostDowngrade());
// How many bytes past the first request is this one