Mercurial > hg
view hgext/automv.py @ 44363:f7459da77f23
nodemap: introduce an option to use mmap to read the nodemap mapping
The performance and memory benefit is much greater if we don't have to copy all
the data in memory for each information. So we introduce an option (on by
default) to read the data using mmap.
This changeset is the last one definition the API for index support nodemap
data. (they have to be able to use the mmaping).
Below are some benchmark comparing the best we currently have in 5.3 with the
final step of this series (using the persistent nodemap implementation in
Rust). The benchmark run `hg perfindex` with various revset and the following
variants:
Before:
* do not use the persistent nodemap
* use the CPython implementation of the index for nodemap
* use mmapping of the changelog index
After:
* use the MixedIndex Rust code, with the NodeTree object for nodemap access
(still in review)
* use the persistent nodemap data from disk
* access the persistent nodemap data through mmap
* use mmapping of the changelog index
The persistent nodemap greatly speed up most operation on very large
repositories. Some of the previously very fast lookup end up a bit slower because
the persistent nodemap has to be setup. However the absolute slowdown is very
small and won't matters in the big picture.
Here are some numbers (in seconds) for the reference copy of mozilla-try:
Revset Before After abs-change speedup
-10000: 0.004622 0.005532 0.000910 × 0.83
-10: 0.000050 0.000132 0.000082 × 0.37
tip 0.000052 0.000085 0.000033 × 0.61
0 + (-10000:) 0.028222 0.005337 -0.022885 × 5.29
0 0.023521 0.000084 -0.023437 × 280.01
(-10000:) + 0 0.235539 0.005308 -0.230231 × 44.37
(-10:) + :9 0.232883 0.000180 -0.232703 ×1293.79
(-10000:) + (:99) 0.238735 0.005358 -0.233377 × 44.55
:99 + (-10000:) 0.317942 0.005593 -0.312349 × 56.84
:9 + (-10:) 0.313372 0.000179 -0.313193 ×1750.68
:9 0.316450 0.000143 -0.316307 ×2212.93
On smaller repositories, the cost of nodemap related operation is not as big, so
the win is much more modest. Yet it helps shaving a handful of millisecond here
and there.
Here are some numbers (in seconds) for the reference copy of mercurial:
Revset Before After abs-change speedup
-10: 0.000065 0.000097 0.000032 × 0.67
tip 0.000063 0.000078 0.000015 × 0.80
0 0.000561 0.000079 -0.000482 × 7.10
-10000: 0.004609 0.003648 -0.000961 × 1.26
0 + (-10000:) 0.005023 0.003715 -0.001307 × 1.35
(-10:) + :9 0.002187 0.000108 -0.002079 ×20.25
(-10000:) + 0 0.006252 0.003716 -0.002536 × 1.68
(-10000:) + (:99) 0.006367 0.003707 -0.002660 × 1.71
:9 + (-10:) 0.003846 0.000110 -0.003736 ×34.96
:9 0.003854 0.000099 -0.003755 ×38.92
:99 + (-10000:) 0.007644 0.003778 -0.003866 × 2.02
Differential Revision: https://phab.mercurial-scm.org/D7894
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Tue, 11 Feb 2020 11:18:52 +0100 |
parents | 687b865b95ad |
children | 89a2afe31e82 |
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# automv.py # # Copyright 2013-2016 Facebook, Inc. # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """check for unrecorded moves at commit time (EXPERIMENTAL) This extension checks at commit/amend time if any of the committed files comes from an unrecorded mv. The threshold at which a file is considered a move can be set with the ``automv.similarity`` config option. This option takes a percentage between 0 (disabled) and 100 (files must be identical), the default is 95. """ # Using 95 as a default similarity is based on an analysis of the mercurial # repositories of the cpython, mozilla-central & mercurial repositories, as # well as 2 very large facebook repositories. At 95 50% of all potential # missed moves would be caught, as well as correspond with 87% of all # explicitly marked moves. Together, 80% of moved files are 95% similar or # more. # # See http://markmail.org/thread/5pxnljesvufvom57 for context. from __future__ import absolute_import from mercurial.i18n import _ from mercurial import ( commands, copies, error, extensions, pycompat, registrar, scmutil, similar, ) configtable = {} configitem = registrar.configitem(configtable) configitem( b'automv', b'similarity', default=95, ) def extsetup(ui): entry = extensions.wrapcommand(commands.table, b'commit', mvcheck) entry[1].append( (b'', b'no-automv', None, _(b'disable automatic file move detection')) ) def mvcheck(orig, ui, repo, *pats, **opts): """Hook to check for moves at commit time""" opts = pycompat.byteskwargs(opts) renames = None disabled = opts.pop(b'no_automv', False) if not disabled: threshold = ui.configint(b'automv', b'similarity') if not 0 <= threshold <= 100: raise error.Abort(_(b'automv.similarity must be between 0 and 100')) if threshold > 0: match = scmutil.match(repo[None], pats, opts) added, removed = _interestingfiles(repo, match) uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True) renames = _findrenames( repo, uipathfn, added, removed, threshold / 100.0 ) with repo.wlock(): if renames is not None: scmutil._markchanges(repo, (), (), renames) return orig(ui, repo, *pats, **pycompat.strkwargs(opts)) def _interestingfiles(repo, matcher): """Find what files were added or removed in this commit. Returns a tuple of two lists: (added, removed). Only files not *already* marked as moved are included in the added list. """ stat = repo.status(match=matcher) added = stat.added removed = stat.removed copy = copies.pathcopies(repo[b'.'], repo[None], matcher) # remove the copy files for which we already have copy info added = [f for f in added if f not in copy] return added, removed def _findrenames(repo, uipathfn, added, removed, similarity): """Find what files in added are really moved files. Any file named in removed that is at least similarity% similar to a file in added is seen as a rename. """ renames = {} if similarity > 0: for src, dst, score in similar.findrenames( repo, added, removed, similarity ): if repo.ui.verbose: repo.ui.status( _(b'detected move of %s as %s (%d%% similar)\n') % (uipathfn(src), uipathfn(dst), score * 100) ) renames[dst] = src if renames: repo.ui.status(_(b'detected move of %d files\n') % len(renames)) return renames