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Ship it! Ship It! - Anthony Gutierrez On Oct. 8, 2013, 1:42 p.m., Mitch Hayenga wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > http://reviews.gem5.org/r/2000/ > ----------------------------------------------------------- > > (Updated Oct. 8, 2013, 1:42 p.m.) > > > Review request for Default. > > > Repository: gem5 > > > Description > ------- > > Extends the classic prefetcher. > > This patch, originally started by Amin Farmahini, extends the classic > prefetcher to work on non-block aligned addresses. Because the existing > prefetchers in gem5 mask off the lower address bits of cache accesses, many > predictable strides fail to be detected. For example, if a load were to > stride by 48 bytes, with 64 byte cachelines, the current stride based > prefetcher would see an access pattern of 0, 64, 64, 128, 192.... Thus not > detecting a constant stride pattern. This patch fixes this, by training the > prefetcher on access and not masking off the lower address bits. > > It also adds the following configuration options: 1) Training/prefetching > only on cache misses, 2) Training/prefetching only on data acceses, 3) > Optionally tagging prefetches with a PC address. #3 allows prefetchers to > train off of prefetch requests in systems with multiple cache levels and > PC-based prefetchers > present at multiple levels. It also effectively allows a pipelining of > prefetch requests (like in POWER4) across multiple levels of cache hierarchy. > > Improves performance on my gem5 configuration by 4.3% for SPECINT and 4.7% > for SPECFP (geomean). > > > Diffs > ----- > > src/mem/cache/prefetch/stride.cc 8bddb3879c16 > src/mem/cache/prefetch/base.cc 8bddb3879c16 > src/mem/cache/prefetch/base.hh 8bddb3879c16 > src/mem/cache/prefetch/Prefetcher.py 8bddb3879c16 > src/mem/cache/cache_impl.hh 8bddb3879c16 > src/mem/request.hh 8bddb3879c16 > > Diff: http://reviews.gem5.org/r/2000/diff/ > > > Testing > ------- > > Benchmarked SPEC2006 simpoints, will post on the dev mailing list with more > detailed results. > > > Thanks, > > Mitch Hayenga > > _______________________________________________ gem5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/gem5-dev
