[Bug] perf utils

[Bob-Chen222]

Checklist

• 1. I have searched related issues but cannot get the expected help.
• 2. The bug has not been fixed in the latest version.
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Describe the bug

multiple_iteration_timeit_from_trace](https://github.com/sgl-project/sglang-jax/blob/main/python/sgl_jax/srt/kernels/utils/perf.py#L77-L102) in python/sgl_jax/srt/kernels/utils/perf.py was reporting host wall time, not device kernel time — inflating measurements 4–10× and ranking candidates by host noise.

Two compounding issues in _extract_marker_durations_ms:

1. The intended MARKER in args.tf_op filter found zero events, because [jax.named_scope](https://github.com/sgl-project/sglang-jax/
   blob/main/python/sgl_jax/srt/kernels/utils/perf.py#L96) wrapping an already-compiled jit at runtime doesn't propagate into HLO op_name (named_scope only injects metadata when active during tracing).
2. The fallback regex match against task matched the host StepTraceAnnotation event, then min_pid biased to the host plane. Those events have no device_duration_ps, so the code read dur — host wall time including block_until_ready.

I want to confirm whether this makes sense and ask for suggestions and I will make a PR to search directly for device plane's event for more accurate kernel time.

Reproduction

Any kernel measurement

Environment

attention-upgrade branch

[depksingh]

When I verified the xprof kernel execution time with the latency that the perf.py returns I saw the values are correct and consistent. A similar anomaly I faced before where if you pass the named_scope to search i.e. the task name, is not present in the xplane file, then it just takes the dur, which is the host time.

Can you please try to debug if the scope name you're sending to the perf.py is correct and inline with the xprof kernel name that's generated by tuner? I faced the same thing, upon debugging found that my scope name was wrong.