Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 9816b1440ae4ae7ef2be80ba086248d29e820aec
https://github.com/WebKit/WebKit/commit/9816b1440ae4ae7ef2be80ba086248d29e820aec
Author: Geoffrey Garen <[email protected]>
Date: 2026-06-03 (Wed, 03 Jun 2026)
Changed paths:
M Source/WTF/Scripts/generate-unified-source-bundles.py
M Source/WebCore/Sources.txt
M Source/WebKit/Sources.txt
M Source/WebKit/SourcesCocoa.txt
M Source/WebKit/SourcesGTK.txt
M Source/WebKitLegacy/SourcesCocoa.txt
M Source/cmake/OptionsMac.cmake
M Source/cmake/WebKitMacros.cmake
Log Message:
-----------
[CMake][Mac] Jumbo unified builds with @cost weighting
https://bugs.webkit.org/show_bug.cgi?id=316219
rdar://178646839
Reviewed by Pascoe.
Speeds up clean build time by about 2 minutes (27.5%).
Raised the unified build member count from 8 to 128. (Up to 128 is
measurably profitable, and beyond that is not.)
To counter-act the potential increase in incremental build time, we
already have:
* adaptive unified builds
* tuned prefix headers
To that, this patch adds @cost annotation for particularly costly unified
build members. @cost is an optional annotation to indicate a file's wall
time cost to compile, relative to the median. It addresses the case where
a unified bundle contains many long pole files. It's not a regression for
an incremental build to wait on one long pole, but it is a regression for
it to wait on many.
I don't think we need a fancy system for keeping @cost always up to date.
If we ever see a long pole in the future, we can slap a new @cost on it.
All incremental build times after first touch (cold) are un-changed.
First touch (cold) times are mostly un-changed on average, but there are
some small losses:
┌────────────────────────────────────────────────────────────┬
│ First touch (cold) incremental build time │
├───────────────────────────┬──────────┬──────────┬──────────┼
│ sub-target │ N=8 │ N=128 │ Δ │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebCoreJSBindings │ 10.3 s │ 8.2 s │ −2.1 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebCoreRenderStyleInlines │ 4.1 s │ 2.0 s │ −2.0 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ JavaScriptCoreJIT │ 1.1 s │ 1.9 s │ +0.7 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebKitNetworkProcess │ 4.1 s │ 4.5 s │ +0.4 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebCoreStyle │ 4.4 s │ 5.7 s │ +1.3 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebCore (platform/) │ 2.8 s │ 4.8 s │ +2.0 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebCoreDOMAndRendering │ 4.4 s │ 6.5 s │ +2.1 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ JavaScriptCore │ 1.1 s │ 3.5 s │ +2.3 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebKitUIProcess │ 2.2 s │ 3.0 s │ +0.7 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebKitShared │ 4.1 s │ 6.9 s │ +2.9 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebKitGPUProcess │ 4.1 s │ 5.2 s │ +1.1 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebKitWebProcess │ 4.7 s │ 9.5 s │ +4.9 s │
├───────────────────────────┼──────────┼──────────┼──────────┼
│ WebCore (Modules/) │ 2.8 s │ 8.7 s │ +5.9 s │
└───────────────────────────┴──────────┴──────────┴──────────┴
Source/cmake/WebKitMacros.cmake:
- Forward WEBKIT_MAX_BUNDLE_SIZE as --max-bundle-size
Source/cmake/OptionsMac.cmake:
- set WEBKIT_MAX_BUNDLE_SIZE 128 (Mac-only for now; other ports can opt
in once we A/B test compile time and validate EWS)
* Source/WTF/Scripts/generate-unified-source-bundles.py:
(bundle_prefix_and_size_for_path):
(SourceFile.__init__):
(BundleManager.add_file): Added support for a file that costs greater
than implicit 1.
(parse_args):
* Source/WebCore/Sources.txt:
* Source/WebKit/Sources.txt:
* Source/WebKit/SourcesCocoa.txt:
* Source/WebKit/SourcesGTK.txt:
* Source/WebKitLegacy/SourcesCocoa.txt: Added cost annotations.
* Source/cmake/OptionsMac.cmake: Set unified bundle member count to 128.
* Source/cmake/WebKitMacros.cmake:
Canonical link: https://commits.webkit.org/314497@main
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