From 2430be2edb0862a7598d0f8f3c8b4a5f77001df8 Mon Sep 17 00:00:00 2001 From: Nikos Nikoleris Date: Thu, 12 Dec 2019 15:49:36 +0000 Subject: mem-cache: Forward snoops when the cache is not responding When the MSHR is handling a request that will make the block dirty the current cache commits respond. When that's not the case the cache should forward any snoops. This CL fixes MSHR::handleSnoop() to implement this behavior. Change-Id: I207e3ca4968fd9528fd4cdbfb3eb95f470b4744d Signed-off-by: Nikos Nikoleris Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23668 Tested-by: kokoro Reviewed-by: Daniel Carvalho --- src/mem/cache/mshr.cc | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/src/mem/cache/mshr.cc b/src/mem/cache/mshr.cc index 1b21546aa..00dbe900b 100644 --- a/src/mem/cache/mshr.cc +++ b/src/mem/cache/mshr.cc @@ -465,6 +465,10 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order) return true; } + // Start by determining if we will eventually respond or not, + // matching the conditions checked in Cache::handleSnoop + const bool will_respond = isPendingModified() && pkt->needsResponse() && + !pkt->isClean(); if (isPendingModified() || pkt->isInvalidate()) { // We need to save and replay the packet in two cases: // 1. We're awaiting a writable copy (Modified or Exclusive), @@ -474,11 +478,6 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order) // to forward the snoop up the hierarchy after the current // transaction completes. - // Start by determining if we will eventually respond or not, - // matching the conditions checked in Cache::handleSnoop - bool will_respond = isPendingModified() && pkt->needsResponse() && - !pkt->isClean(); - // The packet we are snooping may be deleted by the time we // actually process the target, and we consequently need to // save a copy here. Clear flags and also allocate new data as @@ -535,7 +534,7 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order) pkt->setHasSharers(); } - return true; + return will_respond; } MSHR::TargetList -- cgit v1.2.3