[PATCH] D107173: [CSSPGO] Introduce MD5-based context-sensitive profile
Hongtao Yu via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Jul 30 09:59:32 PDT 2021
hoy added inline comments.
================
Comment at: llvm/lib/Transforms/IPO/SampleContextTracker.cpp:222
+ if (!Context.isBaseContext()) {
+ auto Hash = MD5Hash(Context.getContextInMd5());
+ FuncToCtxtProfiles[Context.getGUID()].emplace(Hash, FSamples);
----------------
The ordering based `Hash` in `FuncToCtxtProfiles` is mainly to achieve a consistent context promotion between md5 and non-md5 profiles which in turn gives a consistent codegen. However it is expansive. I tried sorting by the the combination of total sample counts and head sample counts, but still could not get every case covered. I think we might want to do this for non-md5 profile only, to favor md5 performance.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D107173/new/
https://reviews.llvm.org/D107173
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