da1a2d127d
For short builtin calls, the builtins are copied on the heap when they cannot be put close enough to be in range of relative calls. This costs memory, as the embedded builtins are part of the binary, and mapped from the binary, and as a consequence shared with all running processes. Rather than copying the memory, we can remap it at a different address, avoiding the memory cost. This CL does that, on ARM64 macOS only for now. This saves at least ~1.4MiB of memory per V8 process. See below the output of vmmap <PID>: [...] Memory Tag 255 7408308000-740833c000 [ 208K 144K 144K 0K] r-x/rwx SM=ZER Memory Tag 255 740833c000-7408340000 [ 16K 0K 0K 0K] ---/rwx SM=ZER Memory Tag 255 7408344000-7408348000 [ 16K 0K 0K 0K] ---/rwx SM=ZER Memory Tag 255 7408348000-740837c000 [ 208K 144K 144K 0K] r-x/rwx SM=ZER Memory Tag 255 740837c000-740fe80000 [123.0M 0K 0K 0K] ---/rwx SM=ZER mapped file 740fe80000-740ffe4000 [ 1424K 1328K 0K 0K] r-x/rwx SM=COW ...pp/Contents/Frameworks/Chromium Framework.framework/Versions/102.0.4958.0/Chromium Framework Memory Tag 255 740ffe4000-7410000000 [ 112K 0K 0K 0K] ---/rwx SM=ZER The "208K" regions are 256kiB code pages, minus the header and guard pages, meaning that they are code chunks. The mapped file are the remapped builtins, showing that they aren't copied, but remapped from the binary. Bug: chromium:1298417 Change-Id: Ia30a43e671726d01450a7db0ecb7777b34763053 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3553006 Reviewed-by: Toon Verwaest <verwaest@chromium.org> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Igor Sheludko <ishell@chromium.org> Commit-Queue: Benoit Lize <lizeb@chromium.org> Cr-Commit-Position: refs/heads/main@{#79716} |
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| bazel | ||
| build_overrides | ||
| custom_deps | ||
| docs | ||
| gni | ||
| include | ||
| infra | ||
| samples | ||
| src | ||
| test | ||
| testing | ||
| third_party | ||
| tools | ||
| .bazelrc | ||
| .clang-format | ||
| .clang-tidy | ||
| .editorconfig | ||
| .flake8 | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitignore | ||
| .gn | ||
| .mailmap | ||
| .style.yapf | ||
| .vpython | ||
| .vpython3 | ||
| .ycm_extra_conf.py | ||
| AUTHORS | ||
| BUILD.bazel | ||
| BUILD.gn | ||
| CODE_OF_CONDUCT.md | ||
| codereview.settings | ||
| COMMON_OWNERS | ||
| DEPS | ||
| DIR_METADATA | ||
| ENG_REVIEW_OWNERS | ||
| INFRA_OWNERS | ||
| INTL_OWNERS | ||
| LICENSE | ||
| LICENSE.fdlibm | ||
| LICENSE.strongtalk | ||
| LICENSE.v8 | ||
| LOONG_OWNERS | ||
| MIPS_OWNERS | ||
| OWNERS | ||
| PPC_OWNERS | ||
| PRESUBMIT.py | ||
| README.md | ||
| RISCV_OWNERS | ||
| S390_OWNERS | ||
| WATCHLISTS | ||
| WORKSPACE | ||
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.