sanchayanmaity/gem5
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity

mem: Align cache behaviour in atomic when upstream is responding

Browse source 
Adopt the same flow as in timing mode, where the caches on the path to
memory get to keep the line (if present), and we use the
responderHadWritable flag to determine if we need to forward the
(invalidating) packet or not.
This commit is contained in:
Andreas Hansson 2016-02-10 04:08:24 -05:00
parent 986214f181
commit f84ee031cc
1 changed files with 11 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
src/mem/cache/cache.cc vendored
View file

@ -1011,8 +1011,6 @@ Cache::recvAtomic(PacketPtr pkt)
{
// We are in atomic mode so we pay just for lookupLatency here.
Cycles lat = lookupLatency;
// @TODO: make this a parameter
bool last_level_cache = false;
// Forward the request if the system is in cache bypass mode.
if (system->bypassCaches())
@ -1020,30 +1018,18 @@ Cache::recvAtomic(PacketPtr pkt)
promoteWholeLineWrites(pkt);
// follow the same flow as in recvTimingReq, and check if a cache
// above us is responding
if (pkt->cacheResponding()) {
// have to invalidate ourselves and any lower caches even if
// upper cache will be responding
if (pkt->isInvalidate()) {
CacheBlk *blk = tags->findBlock(pkt->getAddr(), pkt->isSecure());
if (blk && blk->isValid()) {
tags->invalidate(blk);
blk->invalidate();
DPRINTF(Cache, "Other cache responding to %s on %#llx (%s):"
" invalidating\n",
pkt->cmdString(), pkt->getAddr(),
pkt->isSecure() ? "s" : "ns");
}
if (!last_level_cache) {
DPRINTF(Cache, "Other cache responding to %s on %#llx (%s):"
" forwarding\n",
pkt->cmdString(), pkt->getAddr(),
pkt->isSecure() ? "s" : "ns");
lat += ticksToCycles(memSidePort->sendAtomic(pkt));
}
} else {
DPRINTF(Cache, "Other cache responding to %s on %#llx: "
"not responding\n",
pkt->cmdString(), pkt->getAddr());
DPRINTF(Cache, "Cache above responding to %#llx (%s): "
"not responding\n",
pkt->getAddr(), pkt->isSecure() ? "s" : "ns");
// if a cache is responding, and it had the line in Owned
// rather than Modified state, we need to invalidate any
// copies that are not on the same path to memory
if (pkt->needsWritable() && !pkt->responderHadWritable()) {
lat += ticksToCycles(memSidePort->sendAtomic(pkt));
}
return lat * clockPeriod();