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view hgext/share.py @ 42743:8c9a6adec67a
rust-discovery: using the children cache in add_missing
The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.
The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.
This is a case where staying on the same side of the interface
between the two languages has clear benefits.
On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.
For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:
Rust version with simple iteration
addcommons: 57.287us
first undecided computation: 184.278334ms
first children cache computation: 131.056us
addmissings iteration: 42.766us
first addinfo total: 185.24 ms
Python + C version
first addcommons: 0.29 ms
addcommons 0.21 ms
first undecided computation 191.35 ms
addmissings 45.75 ms
first addinfo total: 237.77 ms
On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:
Rust version:
first undecided computation: 293.842629ms
first children cache computation: 407.911297ms
addmissings iteration: 34.312869ms
first addinfo total: 776.02 ms
taking initial sample
query 2: sampling time: 1318.38 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings: 143.062us
Python + C version:
first undecided computation 298.13 ms
addmissings 80.13 ms
first addinfo total: 399.62 ms
taking initial sample
query 2: sampling time: 3957.23 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings 52.88 ms
Differential Revision: https://phab.mercurial-scm.org/D6428
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Tue, 16 Apr 2019 01:16:39 +0200 |
parents | 526750cdd02d |
children | 2372284d9457 |
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# Copyright 2006, 2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. '''share a common history between several working directories Automatic Pooled Storage for Clones ----------------------------------- When this extension is active, :hg:`clone` can be configured to automatically share/pool storage across multiple clones. This mode effectively converts :hg:`clone` to :hg:`clone` + :hg:`share`. The benefit of using this mode is the automatic management of store paths and intelligent pooling of related repositories. The following ``share.`` config options influence this feature: ``share.pool`` Filesystem path where shared repository data will be stored. When defined, :hg:`clone` will automatically use shared repository storage instead of creating a store inside each clone. ``share.poolnaming`` How directory names in ``share.pool`` are constructed. "identity" means the name is derived from the first changeset in the repository. In this mode, different remotes share storage if their root/initial changeset is identical. In this mode, the local shared repository is an aggregate of all encountered remote repositories. "remote" means the name is derived from the source repository's path or URL. In this mode, storage is only shared if the path or URL requested in the :hg:`clone` command matches exactly to a repository that was cloned before. The default naming mode is "identity". ''' from __future__ import absolute_import import errno from mercurial.i18n import _ from mercurial import ( bookmarks, commands, error, extensions, hg, registrar, txnutil, util, ) cmdtable = {} command = registrar.command(cmdtable) # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should # be specifying the version(s) of Mercurial they are tested with, or # leave the attribute unspecified. testedwith = 'ships-with-hg-core' @command('share', [('U', 'noupdate', None, _('do not create a working directory')), ('B', 'bookmarks', None, _('also share bookmarks')), ('', 'relative', None, _('point to source using a relative path ' '(EXPERIMENTAL)')), ], _('[-U] [-B] SOURCE [DEST]'), helpcategory=command.CATEGORY_REPO_CREATION, norepo=True) def share(ui, source, dest=None, noupdate=False, bookmarks=False, relative=False): """create a new shared repository Initialize a new repository and working directory that shares its history (and optionally bookmarks) with another repository. .. note:: using rollback or extensions that destroy/modify history (mq, rebase, etc.) can cause considerable confusion with shared clones. In particular, if two shared clones are both updated to the same changeset, and one of them destroys that changeset with rollback, the other clone will suddenly stop working: all operations will fail with "abort: working directory has unknown parent". The only known workaround is to use debugsetparents on the broken clone to reset it to a changeset that still exists. """ hg.share(ui, source, dest=dest, update=not noupdate, bookmarks=bookmarks, relative=relative) return 0 @command('unshare', [], '', helpcategory=command.CATEGORY_MAINTENANCE) def unshare(ui, repo): """convert a shared repository to a normal one Copy the store data to the repo and remove the sharedpath data. """ if not repo.shared(): raise error.Abort(_("this is not a shared repo")) hg.unshare(ui, repo) # Wrap clone command to pass auto share options. def clone(orig, ui, source, *args, **opts): pool = ui.config('share', 'pool') if pool: pool = util.expandpath(pool) opts[r'shareopts'] = { 'pool': pool, 'mode': ui.config('share', 'poolnaming'), } return orig(ui, source, *args, **opts) def extsetup(ui): extensions.wrapfunction(bookmarks, '_getbkfile', getbkfile) extensions.wrapfunction(bookmarks.bmstore, '_recordchange', recordchange) extensions.wrapfunction(bookmarks.bmstore, '_writerepo', writerepo) extensions.wrapcommand(commands.table, 'clone', clone) def _hassharedbookmarks(repo): """Returns whether this repo has shared bookmarks""" if bookmarks.bookmarksinstore(repo): # Kind of a lie, but it means that we skip our custom reads and writes # from/to the source repo. return False try: shared = repo.vfs.read('shared').splitlines() except IOError as inst: if inst.errno != errno.ENOENT: raise return False return hg.sharedbookmarks in shared def getbkfile(orig, repo): if _hassharedbookmarks(repo): srcrepo = hg.sharedreposource(repo) if srcrepo is not None: # just orig(srcrepo) doesn't work as expected, because # HG_PENDING refers repo.root. try: fp, pending = txnutil.trypending(repo.root, repo.vfs, 'bookmarks') if pending: # only in this case, bookmark information in repo # is up-to-date. return fp fp.close() except IOError as inst: if inst.errno != errno.ENOENT: raise # otherwise, we should read bookmarks from srcrepo, # because .hg/bookmarks in srcrepo might be already # changed via another sharing repo repo = srcrepo # TODO: Pending changes in repo are still invisible in # srcrepo, because bookmarks.pending is written only into repo. # See also https://www.mercurial-scm.org/wiki/SharedRepository return orig(repo) def recordchange(orig, self, tr): # Continue with write to local bookmarks file as usual orig(self, tr) if _hassharedbookmarks(self._repo): srcrepo = hg.sharedreposource(self._repo) if srcrepo is not None: category = 'share-bookmarks' tr.addpostclose(category, lambda tr: self._writerepo(srcrepo)) def writerepo(orig, self, repo): # First write local bookmarks file in case we ever unshare orig(self, repo) if _hassharedbookmarks(self._repo): srcrepo = hg.sharedreposource(self._repo) if srcrepo is not None: orig(self, srcrepo)