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Diffstat (limited to 'src/mem/cache/base.hh')
| -rw-r--r-- | src/mem/cache/base.hh | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/mem/cache/base.hh b/src/mem/cache/base.hh index 02b9e2d2e..362381b61 100644 --- a/src/mem/cache/base.hh +++ b/src/mem/cache/base.hh @@ -660,6 +660,33 @@ class BaseCache : public ClockedObject EventFunctionWrapper writebackTempBlockAtomicEvent; /** + * When a block is overwriten, its compression information must be updated, + * and it may need to be recompressed. If the compression size changes, the + * block may either become smaller, in which case there is no side effect, + * or bigger (data expansion; fat write), in which case the block might not + * fit in its current location anymore. If that happens, there are usually + * two options to be taken: + * + * - The co-allocated blocks must be evicted to make room for this block. + * Simpler, but ignores replacement data. + * - The block itself is moved elsewhere (used in policies where the CF + * determines the location of the block). + * + * This implementation uses the first approach. + * + * Notice that this is only called for writebacks, which means that L1 + * caches (which see regular Writes), do not support compression. + * @sa CompressedTags + * + * @param blk The block to be overwriten. + * @param data A pointer to the data to be compressed (blk's new data). + * @param writebacks List for any writebacks that need to be performed. + * @return Whether operation is successful or not. + */ + bool updateCompressionData(CacheBlk *blk, const uint64_t* data, + PacketList &writebacks); + + /** * Perform any necessary updates to the block and perform any data * exchange between the packet and the block. The flags of the * packet are also set accordingly. @@ -1016,6 +1043,9 @@ class BaseCache : public ClockedObject /** Number of replacements of valid blocks. */ Stats::Scalar replacements; + /** Number of data expansions. */ + Stats::Scalar dataExpansions; + /** * @} */ |