Re: [PATCH 0/2] perf script flamegraph: Fix input file name errors

[Ian Rogers]

On Thu, Oct 1, 2026 at 11:20 AM Stephen Brennan
<stephen.s.brennan@xxxxxxxxxx> wrote:
>
> The flamegraph.py script has a "-i" option which it uses in an attempt to
> know the input file name for the data it is processing. But perf itself is
> using that flag and not forwarding its value to the script, so the entire
> strategy won't work. It's further complicated by how the option processing
> is handled in the flamegraph-report script -- details in patch 2.
>
> This series introduces a helper to allow python scripts to see the input
> file name, and then fixes flamegraph.py. Testing with a variety of options
> like below shows that it is using the correct input files in most use cases
> I can think of:
>
> $ export PERF_EXEC_PATH=$(pwd)/tools/perf
>
> $ sudo -E tools/perf/perf script flamegraph -a -F999 -- sleep 1
> dumping data to flamegraph.html
>
> $ sudo -E tools/perf/perf script record flamegraph \
>                           -o myfile.data -a -F999 -- sleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 2.891 MB myfile.data (1832 samples) ]
>
> $ sudo -E tools/perf/perf script report flamegraph -i myfile.data \
>                                  -- -o myfile.html
> dumping data to myfile.html
>
> $ sudo -E tools/perf/perf script \
>        -s tools/perf/scripts/python/flamegraph.py -i myfile.data
> dumping data to flamegraph.html
>
> $ sudo -E tools/perf/perf script record flamegraph \
>        -o - -a -F999 -- sleep 1 \
>     | tools/perf/perf script report flamegraph -i - -- -o manual.html
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 2.936 MB - ]
> dumping data to manual.html

Hi Stephen,

Thank you for the contribution! Unfortunately we recently deleted all
of this code in this series:
https://lore.kernel.org/linux-perf-users/20260926062029.800743-1-irogers@xxxxxxxxxx/
You can find the latest code in the perf-tools-next branch:
https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/
The flamegraph code that now uses perf's python module is here:
https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/python/flamegraph.py?h=perf-tools-next
and we even have some tests now:
https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/tests/shell/test_flamegraph_python.sh?h=perf-tools-next

You may also like to play with the console flamegraph that is part of treport:
https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/python/treport.py?h=perf-tools-next

Thanks,
Ian


> Stephen Brennan (2):
>   tools: perf: add perf_input_name() helper
>   tools: perf: flamegraph.py: fix "Error reading report header"
>
>  .../perf/Documentation/perf-script-python.txt |  1 +
>  .../scripts/python/Perf-Trace-Util/Context.c  | 16 ++++++++++++++
>  tools/perf/scripts/python/flamegraph.py       | 22 +++++++++----------
>  3 files changed, 27 insertions(+), 12 deletions(-)
>
> --
> 2.52.0
>