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A comment on Improving Firefox Responsiveness on macOS. Parent comment

Re:Improving Firefox Responsiveness on macOS by jupp0r on Monday October 10, 2022 @07:01PM (#33157420)
My understanding was that allocators nowadays have cache pools per cpu or thread and only rarely need to lock on global state (when imbalances between pool sizes necessitate shifting resources around).
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Re:Improving Firefox Responsiveness on macOS by saagarjha on Monday October 10, 2022 @07:43PM (#33157693)
You are correct, but there are still places where synchronization is necessary.
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Re:Improving Firefox Responsiveness on macOS by gsvelto on Tuesday October 11, 2022 @02:52AM (#33160207)
They do and so does jemalloc in Firefox, however that lowers contention, it doesn't let you do away with synchronization. Consider this simple scenario: a thread allocates a chunk of memory from its per-thread pool, but the object is later released by another thread. You can't do that w/o synchronization around the pool. Per-CPU pools are even trickier because a thread might be moved around between different CPUs by the scheduler while it's allocating memory. So you need special facilities to implement those in user-space like restartable sequences: https://lwn.net/Articles/650333/
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Re:Improving Firefox Responsiveness on macOS by saagarjha on Tuesday October 11, 2022 @05:00AM (#33160970)
Amusingly macOS also has this as SPI, it's used for the Objective-C runtime.
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