GH-129715: Don't project traces that return to an unknown caller#130024
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brandtbucher merged 3 commits intopython:mainfrom Feb 12, 2025
Merged
GH-129715: Don't project traces that return to an unknown caller#130024brandtbucher merged 3 commits intopython:mainfrom
brandtbucher merged 3 commits intopython:mainfrom
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brandtbucher
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Feb 12, 2025
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Pretty straightforward: if a trace ends by returning or yielding to an unknown caller, don't bother compiling it.
This makes the JIT almost 1% faster, since we're no longer jumping in and out of these "doomed" traces. The biggest gains are on our current "worst" benchmarks (see JIT vs. non-JIT for comparison). It does result in about 7.5% more tier one instructions being executed, since all of these little dead-end traces add up.
The plan is to handle these by "specializing"
RETURN_VALUE,RETURN_GENERATOR, andYIELD_VALUEfor known Python callers, and using that information during trace projection. That will come in follow-up PRs.This also fixes a bug in one of the instrumentation helpers (it was shaken out by this change). If an instruction is
ENTER_EXECUTOR, then it can't be instrumented. However, it is possible forENTER_EXECUTORto live alongside instrumented instructions._DYNAMIC_EXIT#129715