Tachyon hook

[maurycy]

The PR adds support for profiling benchmarks with a Tachyon hook.

It's enabled only during benchmark execution. It supports nearly all flags as environment variables, and there's a guard for versions below 3.15. It's disabled on Windows, since I don't have access to any.

I'm not sure if this should be merged before October 2026, but it's a good way to verify Tachyon itself and offers a new way to profile the whole pyperformance suite.

Basic way to test:

uv run --python 3.15 -m pyperf timeit --hook tachyon '[x**2 for x in range(1000)]'

pyperformance

I was able to run the whole pyperformance suite with it:

PYPERF_TACHYON_OPTS="--flamegraph" \
PYTHONPATH=/home/maurycy/github.com/maurycy/pyperf \
uv run --python 3.15 --with /home/maurycy/github.com/maurycy/pyperf/pyperformance \
python -c "import pyperformance.cli; pyperformance.cli.main()" run \
  --fast \
  --hook tachyon \
  --inherit-environ PYPERF_TACHYON_OPTS

notes

• Beyond the scope, but the hook subsystem could be more granular (any interest?), so WorkerTask etc. wouldn't be included,
• profiling.sampling does not seem to offer a way to stop, except killing the process (not the urgent priority),
• What would be the best way to write a test for it?

[vstinner]

Why not just calling it PYPERF_TACHYON_OPTS?

[maurycy]

@vstinner Changed: 5791a4e

To be honest, I just copied the convention from perf_record:

• https://github.com/psf/pyperf/blob/main/pyperf/_hooks.py#L127

[pablogsal]

• profiling.sampling does not seem to offer a way to stop, except killing the process (not the urgent priority),

We can perhaps add a signal handler to the tachyon CLI invocation so you can request stopping. I think we react already to SIGINT so perhaps that works

[vstinner]

I don't know hooks. How am I supposed to use them?

I tried the timeit command but it doesn't do anything special when using the tachyon hook.

$ PYPERF_TACHYON_EXTRA_OPTS="--flamegraph" python3.15 -m pyperf timeit "[1,2]*1000" --loops 2^17 -p3 --hook tachyon -q
Mean +- std dev: 1.43 us +- 0.01 us

Same issue when running a benchmark script:

$ PYPERF_TACHYON_EXTRA_OPTS="--flamegraph" python3.15 doc/examples/bench_func.py --hook tachyon -p3
....
sleep: Mean +- std dev: 1.07 ms +- 0.00 ms

[maurycy]

I don't know hooks. How am I supposed to use them?

I didn't change Github description example to use PYPERF_TACHYON_OPTS after #230 (comment)

Attaching the flame graphs:

• flamegraph_8181.html
• flamegraph_8174.html
• flamegraph_8167.html

The obvious problem is that it includes WorkerTask, because the hook subsystem is granular.

[vstinner]

LGTM.

My example works with PYPERF_TACHYON_OPTS env var.

[pablogsal]

Thanks for the PR @maurycy