Mercurial > hg
view tests/test-revlog-mmapindex.t @ 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> |
---|---|
date | Fri, 30 Nov 2018 14:35:57 +0100 |
parents | 6ebe899b6551 |
children | 42d2b31cee0b |
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create verbosemmap.py $ cat << EOF > verbosemmap.py > # extension to make util.mmapread verbose > > from __future__ import absolute_import > > from mercurial import ( > extensions, > pycompat, > util, > ) > > def extsetup(ui): > def mmapread(orig, fp): > ui.write(b"mmapping %s\n" % pycompat.bytestr(fp.name)) > ui.flush() > return orig(fp) > > extensions.wrapfunction(util, 'mmapread', mmapread) > EOF setting up base repo $ hg init a $ cd a $ touch a $ hg add a $ hg commit -qm base $ for i in `$TESTDIR/seq.py 1 100` ; do > echo $i > a > hg commit -qm $i > done set up verbosemmap extension $ cat << EOF >> $HGRCPATH > [extensions] > verbosemmap=$TESTTMP/verbosemmap.py > EOF mmap index which is now more than 4k long $ hg log -l 5 -T '{rev}\n' --config experimental.mmapindexthreshold=4k mmapping $TESTTMP/a/.hg/store/00changelog.i 100 99 98 97 96 do not mmap index which is still less than 32k $ hg log -l 5 -T '{rev}\n' --config experimental.mmapindexthreshold=32k 100 99 98 97 96 $ cd ..