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Andreas Haas a7e8c320c6 [wasm] Run sync compilation with kUserBlocking priority
With the recent switch from the tasks API to the jobs API for thread
management within WebAssembly compilation we got the problem that
TurboFan compilation of a previous compilation can block the Liftoff
compilation of a new compilation. With synchronous compilation, this can
cause significant delays for the user. With this CL we increase the
priority of synchronous compilation so that at least synchronous
compilation can only be blocked by other synchronous compilation. This
fixes issues that we saw on autocad.

Why is it okay to increase the priority of synchronous compilation?
* On the main thread, synchronous compilation is only allowed for small
  modules which should not take long to compile. Also, the compilation
  blocks the main thread and should finish as fast as possible.
* On worker threads, delaying other background work is not such a big
  issue.

Downsides:
* This does not only increase the priority of the initial compilation,
  but also for the TurboFan optimization. Similar to above, for small
  modules on the main thread this should not be a big deal because
  compilation is fast. Big modules can only be compiled on worker
  threads.

Note that this is supposed to be a fix for the problems we see at the
moment with autocad on stable and beta. Eventually compilation job
management should be done by the wasm engine for all WebAssembly
compilation, so that not each WebAssemly module has to do its own
compilation job management.

R=clemensb@chromium.org

Bug: chromium:1142686, v8:11088
Change-Id: Iee4948b2fcad944f587918e9452e6888258857f9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2512911
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70923}
2020-11-02 15:43:58 +00:00
build_overrides tracing: Enable using Perfetto client library from Chromium 2020-05-11 11:17:57 +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 tracing: Update proto library build rule and roll Perfetto 2020-10-07 12:49:09 +00:00
include Fix alloc/dealloc size mismatch for v8::BackingStore 2020-11-02 11:57:30 +00:00
infra Add Noavx tests to Linux 32 bots 2020-10-30 11:46:32 +00:00
samples cppgc: Use libplatform as default platform 2020-10-08 18:16:52 +00:00
src [wasm] Run sync compilation with kUserBlocking priority 2020-11-02 15:43:58 +00:00
test [inspector][fuzzer] Add inspector fuzzer 2020-11-02 14:29:08 +00:00
testing build: Remove no-op calls to set_sources_assignment_filter 2020-10-08 14:44:01 +00:00
third_party [csa][cleanup] Remove ParameterMode/TNodify StoreFixedDoubleArrayElement 2020-08-26 17:14:44 +00:00
tools [torque][wasm] generate C++ class and BodyDescriptor for WasmCapiFunctionData 2020-11-02 14:22:56 +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 Revert "[presubmit] Add JS formatting for tools/system-analyzer" 2020-07-17 10:33:40 +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 perf: make GetPositionInfoSlow() faster 2020-10-27 07:15:01 +00:00
BUILD.gn [inspector][fuzzer] Add inspector fuzzer 2020-11-02 14:29:08 +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 Adding vahl@ to the common owners to be able to handle 2020-08-21 09:04:56 +00:00
DEPS Update V8 DEPS. 2020-11-02 03:46:19 +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 Move architecture dependent files 2019-05-28 14:02:15 +00:00
OWNERS Add DIR_METADATA files to v8. 2020-10-20 22:12:28 +00:00
PPC_OWNERS Adding Red Hat to the list of Authorized contributors. 2020-09-16 12:34:39 +00:00
PRESUBMIT.py [presubmit] Allow use of test functions in runtime-test.cc 2020-08-10 12:12:55 +00:00
README.md [docs] Change links from old wiki to v8.dev 2019-03-07 12:13:30 +00:00
S390_OWNERS Adding Red Hat to the list of Authorized contributors. 2020-09-16 12:34:39 +00:00
WATCHLISTS Stop watching for API changes in WATCHLISTS 2020-04-08 07:06:45 +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.