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.
Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
When running the `profiling.sampling` module in pstats mode, the output
can be emitted in two different ways: text to stdout or a binary file
when the `--output` argument is set.
The current documentation and help text is confusing as it does not
distinguish between these two output formats so it may be surprising to
the user to get different formats depending whether `--output` is set or not.
