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A loop split between two hot executors never calls CHECK_EVAL_BREAKER() #117442
Description
When a tight for loop without calls is turned into two traces that transfer directly to each other, it seems that CHECK_EVAL_BREAKER() is never called, and the loop won't be interruptible.
See faster-cpython/ideas#669 (comment), where @brandtbucher and I reasoned that this might occur in the nbody benchmark (when the max trace length is reduced to 400).
While we didn't observe the predicted speedup, we really do believe that in this case the thread is uninterruptible.
@markshannon Any thoughts?
Activity
brandtbucher commentedon Apr 2, 2024
Probably we should insert a
_CHECK_PERIODICat the beginning of a trace starting withJUMP_BACKWARD, rather than checking signals in_JUMP_TO_TOP. That way we also wouldn't need to check signals inENTER_EXECUTOR,_JUMP_TO_TOP, and wherever else is necessary to fix this issue.GH-117442: Check eval-breaker at start (rather than end) of tier 2 lo…
pythonGH-117442: Check eval-breaker at start (rather than end) of tie…