gh-130956: emit AArch64 trampolines only for long jumps#131041
Merged
brandtbucher merged 3 commits intopython:mainfrom Mar 19, 2025
Merged
gh-130956: emit AArch64 trampolines only for long jumps#131041brandtbucher merged 3 commits intopython:mainfrom
brandtbucher merged 3 commits intopython:mainfrom
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Emit the AArch64 trampoline only if the address is more than 27 bits range. Enable the PLT for Linux AArch64: without it no trampolines are emitted at all and symbols are referenced via the GOT.
diegorusso
commented
Mar 10, 2025
Tools/jit/_targets.py
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| # On aarch64 Linux, intrinsics were being emitted and this flag | ||
| # was required to disable them. | ||
| "-mno-outline-atomics", | ||
| "-fplt", |
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This is needed otherwise trampolines are not generated at all and everything is referenced via the GOT. if you prefer, we can have this as separate PR.
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Yeah, this seems like this slows Linux down. Let's drop it.
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brandtbucher
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Mar 18, 2025
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brandtbucher
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Yep, looks good!
Looks like it's ~0.4% slower on Linux, and ~0.8% faster on macOS (with 20-25% faster startup!). Maybe, given the results, we should roll back the new -fplt option for Linux? Otherwise, I think this makes sense to land.
brandtbucher
approved these changes
Mar 19, 2025
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Emit the AArch64 trampoline only if the address is more than 27 bits range.
Enable the PLT for Linux AArch64: without it no trampolines are emitted at all and symbols are referenced via the GOT.