Profiling

Opt-in profiling regions

mpiparticles times its expensive operations with scope-profiler regions named mpiparticles.<operation>: migrate, keep_owned, gather_columns, and the store’s reserve (only when the storage grows), compact, sort_by_key, snapshot and restore. They are tagged "mpiparticles", an opt-in tag, so they stay off (and record nothing) when an application profiles its own code, until it asks for them:

import scope_profiler as sp

sp.setup(enable_tags=["mpiparticles"])

session(enable_tags=...) and ProfilingOptions(enable_tags=...) take the same argument.

The same works without touching the code: enable_tags = ["mpiparticles"] in the TOML configuration, SCOPE_PROFILER_ENABLE_TAGS=mpiparticles in the environment, or scope-profiler run --enable-tag mpiparticles script.py. "*" enables every opt-in tag.

A region that is off costs a few tenths of a microsecond per call, so only operations over all markers are instrumented, never per-marker work.