Improve performance of linker symbol cache under high contention. NFC #24029
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This drastically improves the performance of running the test suite even though most users probably won't see any effect. Prior to this change the symbol generation process itself always happened with the symbol list lock held. Now in the most common cases the symbol list is generated before we grab the lock. before: - hot: 0m25.259s - cold: 1m36.121s after: - hot: 0m21.371s - cold: 0m20.350s
kripken
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kripken
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See tox-dev/filelock#31 And https://stackoverflow.com/a/51070775 Without this change the `cache/symbol_lists` directory ends up full of many lock files that might never get cleaned up (At least since emscripten-core#24029 landed).
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See tox-dev/filelock#31 And https://stackoverflow.com/a/51070775 Without this change the `cache/symbol_lists` directory ends up full of many lock files that might never get cleaned up (At least since emscripten-core#24029 landed).
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See tox-dev/filelock#31 and https://stackoverflow.com/a/51070775. Without this change the `cache/symbol_lists` directory ends up full of many lock files that might never get cleaned up (At least since #24029 landed). I'm also sending this change upstream: tox-dev/filelock#408
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This drastically improves the performance of running the test suite even though most users probably won't see any effect.
Prior to this change the symbol generation process itself always happened with a global symbol list lock held. Now we use a per-symbol-list lock which means that only linker processes with identical linker flags with contend for the lock.
before:
after:
This also happens to fix #18622 since it avoids using
cache.get()which does logging.