| commit | 1075da2675d445494d9a4ff74d004c9787d944ad | [log] [tgz] |
|---|---|---|
| author | Gabriel Marin <gmx@chromium.org> | Mon Jun 22 20:50:56 2020 |
| committer | Commit Bot <commit-bot@chromium.org> | Mon Jun 22 20:50:56 2020 |
| tree | 413ad3850eafb849b9dfc2d14c4634d31631c555 | |
| parent | a7a8e989d5fc82ef90ca97eecf76b6c8cd0a2ea5 [diff] |
tcmalloc: precompute the pointer mask for the doubly linked list MaskPtr is the hottest function in Chrome, accounting for >2% of chrome CPU cycles in the field. Precomputing the mask, cuts the number of machine instructions generated for MaskPtr in half, with similar potential savings to its running time. Moved definitions of doubly-linked list API functions to the .cc file to make the pointer mask local to the free list implementation. Let the compiler make inlining decisions based on profile information. The change shows statistically significant improvements to some timing metrics in a browsing test, https://screenshot.googleplex.com/GTR9nkiaoBt, but shows no effect on speedometer2 score. Full metric results for a few benchmarks are in https://gmx.users.x20web.corp.google.com/crosperf_maskptr/results-section.html BUG=b:141578761 Change-Id: I9c252ab5617a2d30eec556b9951a8426a612c14e Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2255561 Reviewed-by: Will Harris <wfh@chromium.org> Reviewed-by: Gabriel Marin <gmx@chromium.org> Commit-Queue: Gabriel Marin <gmx@chromium.org> Cr-Original-Commit-Position: refs/heads/master@{#780957} Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src Cr-Mirrored-Commit: d57ce8a7828f63b65d673f1f31443ba27e87f19e