[experimental] [AArch64] Reorder RTA functions by runtime call density#9727
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igogo-x86 wants to merge 2 commits intofacebook:masterfrom
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[experimental] [AArch64] Reorder RTA functions by runtime call density#9727igogo-x86 wants to merge 2 commits intofacebook:masterfrom
igogo-x86 wants to merge 2 commits intofacebook:masterfrom
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On AArch64, non-smashable calls to the runtime (movz/movk/blr sequences) are significantly more expensive than on x86 due to instruction encoding overhead. This patch reorders functions during retranslateAll so that functions with the highest runtime call density (weighted by profile execution counts) are placed first in code.hot. The idea is that clustering call-heavy functions near the start of the TC improves icache locality for runtime call sequences. Controlled by two new config options: - Eval.JitRuntimeCallReorder (bool, default: true, AArch64 only) - Eval.JitRuntimeCallReorderLimitMB (uint32, default: 64) Diagnostic output available via TRACE=mcg:6.
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@facebook-github-bot has imported this pull request. If you are a Meta employee, you can view this in D94090083. (Because this pull request was imported automatically, there will not be any future comments.) |
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Hi @igogo-x86 We are hitting some assertion errors in CI:
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@igogo-x86 has updated the pull request. You must reimport the pull request before landing. |
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Hi, @charles-typ |
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On AArch64, non-smashable calls to the runtime (movz/movk/blr sequences) are significantly more expensive than on x86 due to instruction encoding overhead. This patch reorders functions during retranslateAll so that functions with the highest runtime call density (weighted by profile execution counts) are placed first in code.hot.
The idea is that clustering call-heavy functions near the start of the TC improves icache locality for runtime call sequences.
Controlled by two new config options:
Diagnostic output available via TRACE=mcg:6.