Mercurial > hg
view hgdemandimport/tracing.py @ 41247:a89b20a49c13
rust-cpython: using MissingAncestors from Python code
As precedently done with LazyAncestors on cpython.rs, we test for the
presence of the 'rustext' module.
incrementalmissingrevs() has two callers within the Mercurial core:
`setdiscovery.partialdiscovery` and the `only()` revset.
This move shows a significant discovery performance improvement
in cases where the baseline is slow: using perfdiscovery on the PyPy
repos, prepared with `contrib/discovery-helper <repo> 50 100`, we
get averaged medians of 403ms with the Rust version vs 742ms without
(about 45% better).
But there are still indications that performance can be worse in cases
the baseline is fast, possibly due to the conversion from Python to
Rust and back becoming the bottleneck. We could measure this on
mozilla-central in cases were the delta is just a few changesets.
This requires confirmation, but if that's the reason, then an
upcoming `partialdiscovery` fully in Rust should solve the problem.
Differential Revision: https://phab.mercurial-scm.org/D5551
author | Georges Racinet <georges.racinet@octobus.net> |
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date | Fri, 30 Nov 2018 14:35:57 +0100 |
parents | 452790284a15 |
children | d0b8a3cfd732 |
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# Support code for event tracing in Mercurial. Lives in demandimport # so it can also be used in demandimport. # # Copyright 2018 Google LLC. # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import contextlib import os _pipe = None _checked = False @contextlib.contextmanager def log(whencefmt, *whenceargs): global _pipe, _session, _checked if _pipe is None: if _checked: yield return _checked = True if 'HGCATAPULTSERVERPIPE' not in os.environ: yield return _pipe = open(os.environ['HGCATAPULTSERVERPIPE'], 'w', 1) _session = os.environ.get('HGCATAPULTSESSION', 'none') whence = whencefmt % whenceargs try: # Both writes to the pipe are wrapped in try/except to ignore # errors, as we can see mysterious errors in here if the pager # is active. Presumably other conditions could trigger # problems too. try: _pipe.write('START %s %s\n' % (_session, whence)) except IOError: pass yield finally: try: _pipe.write('END %s %s\n' % (_session, whence)) except IOError: pass