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gh-138122: Add differential flame graph#145785
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ivonastojanovic wants to merge 2 commits intopython:mainfrom
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gh-138122: Add differential flame graph#145785ivonastojanovic wants to merge 2 commits intopython:mainfrom
ivonastojanovic wants to merge 2 commits intopython:mainfrom
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Differential flame graphs compare two profiling runs and highlight whereperformance has changed. This makes it easier to detect regressionsintroduced by code changes and to verify that optimizations have theintended effect.The visualization renders the current profile with frame widthsrepresenting current time consumption. Color is then applied to show thedifference relative to the baseline profile: red gradients indicateregressions, while blue gradients indicate improvements.Some call paths may disappear entirely between profiles. These arereferred to as elided stacks and occur when optimizations remove codepaths or when certain branches stop executing. When elided stacks arepresent, an "Elided" toggle is displayed, allowing the user to switchbetween the main differential view and a view showing only the removedpaths.
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ivonastojanovic commentedMar 10, 2026
I’m a bit stuck on what colors we should use for new vs deleted functions. Right now:
But I’m not sure if we should even treat them differently from other functions visually. From a perf perspective it’s kind of confusing:
So I’m not sure what the right visual semantics are here. Curious what you think 🙂 |
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Differential flame graphs compare two profiling runs and highlight where performance has changed. This makes it easier to detect regressions introduced by code changes and to verify that optimizations have the intended effect.
The visualization renders the current profile with frame widths representing current time consumption. Color is then applied to show the difference relative to the baseline profile: red gradients indicate regressions, while blue gradients indicate improvements.
Some call paths may disappear entirely between profiles. These are referred to as elided stacks and occur when optimizations remove code paths or when certain branches stop executing. When elided stacks are present, an "Elided" toggle is displayed, allowing the user to switch between the main differential view and a view showing only the removed paths.
Differential view
Elided view
CC:@pablogsal@lkollar
📚 Documentation preview 📚:https://cpython-previews--145785.org.readthedocs.build/