RESOLVED FIXED299819
[VideoFrame]: ~10× slower VideoFrame construction in Safari Technology Preview vs. identical WebKit CI build; 
https://bugs.webkit.org/show_bug.cgi?id=299819
Summary [VideoFrame]: ~10× slower VideoFrame construction in Safari Technology Previe...
Yury Yarashevich
Reported 2025-09-29 13:12:20 PDT
Originally reported in Slack: https://webkit.slack.com/archives/CU5LWFM28/p1758140505177199 ~10× slower VideoFrame construction (copy/format-convert from large Uint8Array) in Safari Technology Preview vs. identical WebKit CI build; differences point at runtime memory allocation/mapping behavior (different libsystem_malloc paths: mach_vm_map/mach_vm_deallocate/madvise vs. free_large/szone_free) and extra zero-fills from Accelerate.
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Yury Yarashevich
Comment 1 2025-09-29 13:14:11 PDT
Because it's impossible to enable new secure allocator predictably on local build of WebKit I want to try specilatively disable multi threading when accelerate called. I suspend it might incur more overhead than performance will especially considering significantly higher total CPU usage.
Yury Yarashevich
Comment 2 2025-09-29 13:29:00 PDT
Pull request: https://github.com/WebKit/WebKit/pull/51522
EWS
Comment 3 2025-09-30 15:18:35 PDT
Committed 300781@main (ecb227c4bef9): <https://commits.webkit.org/300781@main> Reviewed commits have been landed. Closing PR #51522 and removing active labels.
Radar WebKit Bug Importer
Comment 4 2025-09-30 15:20:45 PDT
<rdar://problem/161686736>
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