Disable flamegraph uploads for walltime benchmarks

[AlexWaygood]

Reverts #20409

Prior to 25c13ea, the walltime benchmarks CI job took around 10-11 minutes. It now seems to be taking around 17-18 minutes to complete, which is a pretty major slowdown and somewhat annoying if you're waiting for benchmark results on a PR! See e.g. https://github.com/astral-sh/ruff/actions/runs/17738649543/job/50411336184

[github-actions]

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[silamon]

Maybe try running with environment variable CODSPEED_PERF_ENABLED=false, since it has been enabled by default, while it was not before.

[MichaReiser]

Can we keep the mode lines, it makes upgrading easier (a rennovate PR rather than having to do the upgrade manually)

[MichaReiser]

I pinged the codspeed folks. I'd suggest to maybe give them a few hours to fix this on their side.

[MichaReiser]

I think @silamon is on to something. Codspeed now enables perf profiles for wallspeed benchmarks (you now see a flamegraph for walltime benchmarks too). I can't say just yet if they'll be useful or if our flamegraphs are too large but it's certainly nice to have more than just: It got slower or faster

[MichaReiser]

We should try CODSPEED_PERF_ENABLED=false or accept the regression in return for now having flamegraphs

[AlexWaygood]

https://codspeed.io/astral-sh/ruff/branches/alex%2Fsubtyping-between-protocols?runnerMode=WallTime has some flamegraphs for #20368 (comment) but I don't find them useful personally. The regression in CI time is very significant, however; I'm finding it very frustrating waiting for CI to finish on #20368!

We should try CODSPEED_PERF_ENABLED=false

I've pushed a commit trying this out

[AlexWaygood]

Nice, we're back to the walltime benchmarks completing in 10-11 minutes. Though there are now a lot of lines like this in the logs that I don't know the meaning of:

  Failed to send benchmark URI to runner: FIFO does not exist: /tmp/runner.ctl.fifo

[MichaReiser]

Thank you. I'm fine disabling this for now. It might be worth adding a comment explaining why we disable the perf uploads (because they would be nice)