[PATCH] D58327: [Dominators] Simplify and optimize path compression used in link-eval forest.

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

> In addition, make sure that your performance governor is set to performance and that you pin the process to a single cpu core with its sibling disabled. (like in https://llvm.org/docs/Benchmarking.html#linux). Benchmarking on x86 is hard.

Thanks for the pointer! Here is the performance number of `perf stat -r 10 taskset -c 0 ~/llvm/Release/bin/opt -passes=$(printf '%.0srequire<domtree>,invalidate<domtree>,' {1..1000})'require<domtree>' -disable-output /tmp/p/sqlite-autoconf-3270100/sqlite3.bc`
I'm very new to the optimization part of llvm.. Let me know if there is better way to measure domtree construction.

Before: 9.8444 +- 0.0279 seconds time elapsed  ( +-  0.28% )
After: 9.3996 +- 0.0170 seconds time elapsed  ( +-  0.18% )

I've tried this thrice and can reproduce similar comparison results.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D58327/new/

https://reviews.llvm.org/D58327