`trace.profiler.threshold` is too coarse

Prerequisites

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• Reduce the issue to a minimal, self-contained, reproducible test case.
  Avoid dependencies to Mathlib or Batteries.
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Description

set_option trace.profiler.threshold is very helpful for filtering profiles, but 1ms of resolution is too coarse; using a value of 1 doesn't capture enough data, and using a value of 0 captures way too much.

Context

@hrmacbeth, @robertylewis and I are trying to profile and speedup linarith; with a threshold of 1 we miss most of the cost paid by thousands of calls to MetaM.mkAppM, while with a threshold of 0 the recorded data is too large and never finishes writing out to the profile file.

Steps to Reproduce

Run

set_option trace.profiler.threshold 0.0001
set_option trace.profiler.threshold 100ns

Expected behavior: One of the above should be legal

Actual behavior: Neither is valid syntax, as lean options cannot hold durations or ofScientific literals

Versions

4.14.0

Additional Information

Impact

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Start by reproducing the two set_option trace.profiler.threshold examples in a minimal Lean test case and inspect how this option is parsed and applied. The change is done when a sub-millisecond threshold such as 0.0001 or 100ns is accepted and provides finer profiler filtering without breaking existing values.