gh-138122: Add exception profiling mode to the sampling profiler #142561
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When profiling code it's often valuable to understand what code paths are executing while exceptions are being handled. The new --mode=exception option filters samples to only include threads that have an active exception, making it easy to identify hot spots in error handling code without noise from normal execution paths. This works by checking both the thread's current_exception (for exceptions being raised/propagated) and exc_info (for exceptions being handled in except blocks). The feature integrates with the existing profiler infrastructure including the live TUI, flamegraph output, and gecko format for Firefox Profiler visualization.
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savannahostrowski
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Dec 11, 2025
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savannahostrowski
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Thanks for the reviews @StanFromIreland and @savannahostrowski ! |
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When profiling code it's often valuable to understand what
code paths are executing while exceptions are being handled. The new
--mode=exception option filters samples to only include threads that
have an active exception, making it easy to identify hot spots in error
handling code without noise from normal execution paths.
This works by checking both the thread's current_exception (for
exceptions being raised/propagated) and exc_info (for exceptions being
handled in except blocks). The feature integrates with the existing
profiler infrastructure including the live TUI, flamegraph output, and
gecko format for Firefox Profiler visualization.
📚 Documentation preview 📚: https://cpython-previews--142561.org.readthedocs.build/