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machenbach authored
Revert of [heap] Parallel newspace evacuation, semispace copy, and compaction \o/ (patchset #16 id:620001 of https://codereview.chromium.org/1577853007/ ) Reason for revert: [Sheriff] Leads to crashes on all webrtc chromium testers, e.g.: https://build.chromium.org/p/chromium.webrtc/builders/Mac%20Tester/builds/49664 Original issue's description: > [heap] Parallel newspace evacuation, semispace copy, and compaction \o/ > > All parallelism can be turned off using --predictable, or --noparallel-compaction. > > This patch completely parallelizes > - semispace copy: from space -> to space (within newspace) > - newspace evacuation: newspace -> oldspace > - oldspace compaction: oldspace -> oldspace > > Previously newspace has been handled sequentially (semispace copy, newspace > evacuation) before compacting oldspace in parallel. However, on a high level > there are no dependencies between those two actions, hence we parallelize them > altogether. We base the number of evacuation tasks on the overall set of > to-be-processed pages (newspace + oldspace compaction pages). > > Some low-level details: > - The hard cap on number of tasks has been lifted > - We cache store buffer entries locally before merging them back into the global > StoreBuffer in a finalization phase. > - We cache AllocationSite operations locally before merging them back into the > global pretenuring storage in a finalization phase. > - AllocationSite might be compacted while they would be needed for newspace > evacuation. To mitigate any problems we defer checking allocation sites for > newspace till merging locally buffered data. > > CQ_EXTRA_TRYBOTS=tryserver.v8:v8_linux_arm64_gc_stress_dbg,v8_linux_gc_stress_dbg,v8_mac_gc_stress_dbg,v8_linux64_asan_rel,v8_linux64_tsan_rel,v8_mac64_asan_rel > BUG=chromium:524425 > LOG=N > R=hpayer@chromium.org, ulan@chromium.org > > Committed: https://crrev.com/8f0fd8c0370ae8c5aab56491b879d7e30c329062 > Cr-Commit-Position: refs/heads/master@{#33523} TBR=hpayer@chromium.org,ulan@chromium.org,mlippautz@chromium.org # Skipping CQ checks because original CL landed less than 1 days ago. NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true BUG=chromium:524425 Review URL: https://codereview.chromium.org/1643473002 Cr-Commit-Position: refs/heads/master@{#33539}
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