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author | Steve Reinhardt <stever@gmail.com> | 2008-02-26 20:17:26 -0800 |
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committer | Steve Reinhardt <stever@gmail.com> | 2008-02-26 20:17:26 -0800 |
commit | bdf33239151c7fcc194f6f9b8c62eb313c933755 (patch) | |
tree | 813955010ce9920d1f550133c5a19216b066a745 /src/mem/cache/cache_impl.hh | |
parent | 8c0baf2ce478b16d351feb1f0ce147049f3a04f6 (diff) | |
download | gem5-bdf33239151c7fcc194f6f9b8c62eb313c933755.tar.xz |
Cache: better comments particularly regarding writeback situation.
--HG--
extra : convert_revision : 59ff9ee63ee0fec5a7dfc27b485b737455ccf362
Diffstat (limited to 'src/mem/cache/cache_impl.hh')
-rw-r--r-- | src/mem/cache/cache_impl.hh | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh index d4fbc90a5..15de76532 100644 --- a/src/mem/cache/cache_impl.hh +++ b/src/mem/cache/cache_impl.hh @@ -439,12 +439,12 @@ Cache<TagStore>::timingAccess(PacketPtr pkt) } #if 0 + /** @todo make the fast write alloc (wh64) work with coherence. */ + PacketList writebacks; // If this is a block size write/hint (WH64) allocate the block here // if the coherence protocol allows it. - /** @todo make the fast write alloc (wh64) work with coherence. */ - /** @todo Do we want to do fast writes for writebacks as well? */ if (!blk && pkt->getSize() >= blkSize && coherence->allowFastWrites() && (pkt->cmd == MemCmd::WriteReq || pkt->cmd == MemCmd::WriteInvalidateReq) ) { @@ -517,6 +517,7 @@ Cache<TagStore>::timingAccess(PacketPtr pkt) } +// See comment in cache.hh. template<class TagStore> PacketPtr Cache<TagStore>::getBusPacket(PacketPtr cpu_pkt, BlkType *blk, @@ -529,14 +530,11 @@ Cache<TagStore>::getBusPacket(PacketPtr cpu_pkt, BlkType *blk, return NULL; } - if (!blkValid && - (cpu_pkt->cmd == MemCmd::Writeback || - cpu_pkt->cmd == MemCmd::UpgradeReq)) { - // For now, writebacks from upper-level caches that - // completely miss in the cache just go through. If we had - // "fast write" support (where we could write the whole - // block w/o fetching new data) we might want to allocate - // on writeback misses instead. + if (!blkValid && (cpu_pkt->cmd == MemCmd::Writeback || + cpu_pkt->cmd == MemCmd::UpgradeReq)) { + // Writebacks that weren't allocated in access() and upgrades + // from upper-level caches that missed completely just go + // through. return NULL; } |