gh-138122: Add thread status statistics to flamegraph profiler#141900
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pablogsalforce-pushed the flamegraph-better branch from c226154 to 3e0224fComparepablogsalforce-pushed the flamegraph-better branch from 3e0224f to 21bbd24Compare
…raph profiler The flamegraph profiler now collects thread state information (GIL held, GIL released, waiting for GIL, and garbage collection activity) during sampling and displays it in an interactive statistics bar. This helps users identify GIL contention and understand thread behavior patterns. Statistics are calculated both in aggregate and per-thread. When filtering the flamegraph to a specific thread, the display updates to show that thread's metrics. In GIL-only profiling mode, GIL-related statistics are hidden since they aren't meaningful in that context. The collection logic was refactored to process each sample in a single pass rather than iterating through threads multiple times. GC frame detection now uses a shared helper that consistently handles both tuple and object frame formats. Per-thread GC percentages now use total samples as the denominator instead of per-thread sample counts. This makes them directly comparable with aggregate statistics and easier to interpret when threads appear in different numbers of samples. The JavaScript includes null checks for DOM access and validates data availability before rendering. Tests verify the JSON structure, percentage calculations, and edge cases like zero samples, using only public APIs.
pablogsalforce-pushed the flamegraph-better branch from 21bbd24 to 9694d5aCompare This comment was marked as off-topic.
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pablogsal commented Nov 24, 2025
… flamegraph profiler
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ivonastojanovic left a comment
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Looks good to me! One small thing: for the percentages in the thread-stats-bar, maybe we should use the same rounding as the flamegraph nodes so everything is consistent.
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Co-authored-by: ivonastojanovic <80911834+ivonastojanovic@users.noreply.github.com>
pablogsal merged commit ea51e74 into python:main 46 checks passed
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StanFromIreland pushed a commit to StanFromIreland/cpython that referenced this pull request Dec 6, 2025
…ython#141900) Co-authored-by: ivonastojanovic <80911834+ivonastojanovic@users.noreply.github.com>
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The flamegraph profiler now collects thread state information (GIL held, GIL released, waiting for GIL, and garbage collection activity) during sampling and displays it in an interactive statistics bar. This helps users identify GIL contention and understand thread behavior patterns.
Statistics are calculated both in aggregate and per-thread. When filtering the flamegraph to a specific thread, the display updates to show that thread's metrics. In GIL-only profiling mode, GIL-related statistics are hidden since they aren't meaningful in that context.
Per-thread GC percentages now use total samples as the denominator instead of per-thread sample counts. This makes them directly comparable with aggregate statistics and easier to interpret when threads appear in different numbers of samples.