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Dominik Inführ d5416b9918 [codegen, heap] Improve TimeToSafepoint for concurrent compilation
TimeToSafepoint is the time needed for all background threads to enter
a safepoint after the GC was started on the main thread. This CL
improves that metric during concurrent compilation to bytecode by doing:

1) Park the LocalIsolate during
   InterpreterCompilationJob::ExecuteJobImpl. There are no concurrent
   heap accesses happening while generating bytecode for now. So instead
   of manually placing Safepoint() invocations in the code, simply park
   the local isolate.
2) Destroy the LocalIsolate before the ReleaseParser operation. I've
   seen this take around 2ms, which regressed TimeToSafepoint a lot.
3) Add explicit safepoints to concurrent allocations. This covers the
   rest of the code and from what I've seen so far this is good enough
   to keep TimeToSafepoint around a few microseconds.

I've still seen TimeToSafepoint events with 20-80 microseconds but those
were quite rare and always seemed to be related to Turbofan.

AsLocalIsolate() is necessary in generic code to convert both Isolate
and LocalIsolate to LocalIsolate.

Bug: v8:10315
Change-Id: Idaf9f04ffdf850d0ab0081ec372cc384a9fe7ef9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2663159
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72618}
2021-02-10 08:37:48 +00:00
.github [github] Close PRs created on the V8 GitHub mirror automatically 2021-01-12 08:39:59 +00:00
build_overrides [build] Remove obsolete gn flag 2021-01-11 15:50:59 +00:00
custom_deps Use relative paths to OWNERS files 2019-08-12 13:52:52 +00:00
docs Add OWNERS for docs/ 2019-05-15 12:06:15 +00:00
gni Add RISC-V backend 2021-02-09 17:06:36 +00:00
include Add RISC-V backend 2021-02-09 17:06:36 +00:00
infra Add RISC-V backend 2021-02-09 17:06:36 +00:00
samples cppgc: Avoid initializing cppgc platform through V8 2021-02-09 08:26:11 +00:00
src [codegen, heap] Improve TimeToSafepoint for concurrent compilation 2021-02-10 08:37:48 +00:00
test Fix Intl.DisplayNames language canoncalization 2021-02-10 02:59:43 +00:00
testing build: Remove no-op calls to set_sources_assignment_filter 2020-10-08 14:44:01 +00:00
third_party Remove tebbi from OWNERS and TODOs 2021-01-21 13:23:00 +00:00
tools Add RISC-V backend 2021-02-09 17:06:36 +00:00
.clang-format [clang-format] Don't derive pointer alignment 2017-01-17 09:28:19 +00:00
.clang-tidy [tool] Remove unfixed clang-tidy warnings to ease use. 2018-10-26 07:40:32 +00:00
.editorconfig Add .editorconfig 2017-07-28 13:39:24 +00:00
.flake8 Add .flake8 to allow for python style checking. 2019-07-19 21:44:03 +00:00
.git-blame-ignore-revs [infra] Update .git-blame-ignore-revs 2020-03-03 12:59:13 +00:00
.gitattributes .gitattributes: Mark minified emscripten js files as -diff 2018-09-19 16:27:10 +00:00
.gitignore [build] Remove legacy binutils 2021-01-08 12:33:31 +00:00
.gn [build] Dynamically decide if to use system xcode 2019-07-29 08:20:24 +00:00
.vpython [tools] Implement confidence-based number of runs 2019-05-09 09:42:28 +00:00
.ycm_extra_conf.py Fix ycm config for headers without source 2019-12-09 11:59:21 +00:00
AUTHORS Add RISC-V backend 2021-02-09 17:06:36 +00:00
BUILD.gn [codegen][frames] Generalize argument padding slot code 2021-02-09 19:41:58 +00:00
CODE_OF_CONDUCT.md Explicitly state that the Chromium Code of Conduct also applies to V8 2016-03-02 09:51:24 +00:00
codereview.settings Make Gerrit the default code review for V8 2017-06-30 17:37:37 +00:00
COMMON_OWNERS Remove tebbi from OWNERS and TODOs 2021-01-21 13:23:00 +00:00
DEPS Roll Test262 2021-02-09 09:09:59 +00:00
DIR_METADATA Add DIR_METADATA files to v8. 2020-10-20 22:12:28 +00:00
ENG_REVIEW_OWNERS Add eng review owners as escalation path 2019-05-15 19:12:10 +00:00
INFRA_OWNERS Add team members as owners 2020-08-18 08:29:04 +00:00
INTL_OWNERS add ftang as owner 2020-04-24 19:19:36 +00:00
LICENSE [wasm] Draft version of C/C++ Wasm API 2019-04-17 16:00:26 +00:00
LICENSE.fdlibm Add LICENSE.fdlibm for all the fdlibm imported sources. 2016-06-09 07:17:03 +00:00
LICENSE.strongtalk Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
LICENSE.v8 Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
MIPS_OWNERS [mips] Request to be an owner of MIPS files 2020-11-23 09:43:49 +00:00
OWNERS Add RISC-V backend 2021-02-09 17:06:36 +00:00
PPC_OWNERS Adding myself to relevant OWNERS files. 2020-11-02 16:37:28 +00:00
PRESUBMIT.py cppgc: Add testing API structure 2021-02-03 16:00:37 +00:00
README.md [docs] Change links from old wiki to v8.dev 2019-03-07 12:13:30 +00:00
RISCV_OWNERS Add RISC-V backend 2021-02-09 17:06:36 +00:00
S390_OWNERS Adding myself to relevant OWNERS files. 2020-11-02 16:37:28 +00:00
WATCHLISTS Add a watchlist for ieee754.(cc|h) changes. 2021-01-11 18:10:19 +00:00

V8 JavaScript Engine

V8 is Google's open source JavaScript engine.

V8 implements ECMAScript as specified in ECMA-262.

V8 is written in C++ and is used in Google Chrome, the open source browser from Google.

V8 can run standalone, or can be embedded into any C++ application.

V8 Project page: https://v8.dev/docs

Getting the Code

Checkout depot tools, and run

    fetch v8

This will checkout V8 into the directory v8 and fetch all of its dependencies. To stay up to date, run

    git pull origin
    gclient sync

For fetching all branches, add the following into your remote configuration in .git/config:

    fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
    fetch = +refs/tags/*:refs/tags/*

Contributing

Please follow the instructions mentioned at v8.dev/docs/contribute.