From 78a97b1847e77a60cf085137a37492a18db2dfb8 Mon Sep 17 00:00:00 2001 From: Nikos Nikoleris Date: Mon, 5 Dec 2016 16:48:25 -0500 Subject: mem: Always use InvalidateReq to service WriteLineReq misses Previously, a WriteLineReq that missed in a cache would send out an InvalidateReq if the block lookup failed or an UpgradeReq if the block lookup succeeded but the block had sharers. This changes ensures that a WriteLineReq always sends an InvalidateReq to invalidate all copies of the block and satisfy the WriteLineReq. Change-Id: I207ff5b267663abf02bc0b08aeadde69ad81be61 Reviewed-by: Andreas Hansson --- src/mem/cache/cache.cc | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'src') diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc index 6f02edb82..48382814f 100644 --- a/src/mem/cache/cache.cc +++ b/src/mem/cache/cache.cc @@ -924,7 +924,13 @@ Cache::createMissPacket(PacketPtr cpu_pkt, CacheBlk *blk, // write miss on a shared owned block will generate a ReadExcl, // which will clobber the owned copy. const bool useUpgrades = true; - if (blkValid && useUpgrades) { + if (cpu_pkt->cmd == MemCmd::WriteLineReq) { + assert(!blkValid || !blk->isWritable()); + // forward as invalidate to all other caches, this gives us + // the line in Exclusive state, and invalidates all other + // copies + cmd = MemCmd::InvalidateReq; + } else if (blkValid && useUpgrades) { // only reason to be here is that blk is read only and we need // it to be writable assert(needsWritable); @@ -937,11 +943,6 @@ Cache::createMissPacket(PacketPtr cpu_pkt, CacheBlk *blk, // where the determination the StoreCond fails is delayed due to // all caches not being on the same local bus. cmd = MemCmd::SCUpgradeFailReq; - } else if (cpu_pkt->cmd == MemCmd::WriteLineReq) { - // forward as invalidate to all other caches, this gives us - // the line in Exclusive state, and invalidates all other - // copies - cmd = MemCmd::InvalidateReq; } else { // block is invalid cmd = needsWritable ? MemCmd::ReadExReq : -- cgit v1.2.3