Mercurial > hg
view hgext/strip.py @ 30212:260af19891f2
changegroup: increase write buffer size to 128k
By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.
This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.
It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.
When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).
This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 16 Oct 2016 13:35:23 -0700 |
parents | d5883fd055c6 |
children | 46ba2cdda476 |
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"""strip changesets and their descendants from history This extension allows you to strip changesets and all their descendants from the repository. See the command help for details. """ from __future__ import absolute_import from mercurial.i18n import _ from mercurial import ( bookmarks as bookmarksmod, cmdutil, error, hg, lock as lockmod, merge, node as nodemod, repair, scmutil, util, ) nullid = nodemod.nullid release = lockmod.release cmdtable = {} command = cmdutil.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' def checksubstate(repo, baserev=None): '''return list of subrepos at a different revision than substate. Abort if any subrepos have uncommitted changes.''' inclsubs = [] wctx = repo[None] if baserev: bctx = repo[baserev] else: bctx = wctx.parents()[0] for s in sorted(wctx.substate): wctx.sub(s).bailifchanged(True) if s not in bctx.substate or bctx.sub(s).dirty(): inclsubs.append(s) return inclsubs def checklocalchanges(repo, force=False, excsuffix=''): cmdutil.checkunfinished(repo) s = repo.status() if not force: if s.modified or s.added or s.removed or s.deleted: _("local changes found") # i18n tool detection raise error.Abort(_("local changes found" + excsuffix)) if checksubstate(repo): _("local changed subrepos found") # i18n tool detection raise error.Abort(_("local changed subrepos found" + excsuffix)) return s def strip(ui, repo, revs, update=True, backup=True, force=None, bookmarks=None): wlock = lock = None try: wlock = repo.wlock() lock = repo.lock() if update: checklocalchanges(repo, force=force) urev, p2 = repo.changelog.parents(revs[0]) if (util.safehasattr(repo, 'mq') and p2 != nullid and p2 in [x.node for x in repo.mq.applied]): urev = p2 hg.clean(repo, urev) repo.dirstate.write(repo.currenttransaction()) repair.strip(ui, repo, revs, backup) repomarks = repo._bookmarks if bookmarks: with repo.transaction('strip') as tr: if repo._activebookmark in bookmarks: bookmarksmod.deactivate(repo) for bookmark in bookmarks: del repomarks[bookmark] repomarks.recordchange(tr) for bookmark in sorted(bookmarks): ui.write(_("bookmark '%s' deleted\n") % bookmark) finally: release(lock, wlock) @command("strip", [ ('r', 'rev', [], _('strip specified revision (optional, ' 'can specify revisions without this ' 'option)'), _('REV')), ('f', 'force', None, _('force removal of changesets, discard ' 'uncommitted changes (no backup)')), ('', 'no-backup', None, _('no backups')), ('', 'nobackup', None, _('no backups (DEPRECATED)')), ('n', '', None, _('ignored (DEPRECATED)')), ('k', 'keep', None, _("do not modify working directory during " "strip")), ('B', 'bookmark', [], _("remove revs only reachable from given" " bookmark"))], _('hg strip [-k] [-f] [-B bookmark] [-r] REV...')) def stripcmd(ui, repo, *revs, **opts): """strip changesets and all their descendants from the repository The strip command removes the specified changesets and all their descendants. If the working directory has uncommitted changes, the operation is aborted unless the --force flag is supplied, in which case changes will be discarded. If a parent of the working directory is stripped, then the working directory will automatically be updated to the most recent available ancestor of the stripped parent after the operation completes. Any stripped changesets are stored in ``.hg/strip-backup`` as a bundle (see :hg:`help bundle` and :hg:`help unbundle`). They can be restored by running :hg:`unbundle .hg/strip-backup/BUNDLE`, where BUNDLE is the bundle file created by the strip. Note that the local revision numbers will in general be different after the restore. Use the --no-backup option to discard the backup bundle once the operation completes. Strip is not a history-rewriting operation and can be used on changesets in the public phase. But if the stripped changesets have been pushed to a remote repository you will likely pull them again. Return 0 on success. """ backup = True if opts.get('no_backup') or opts.get('nobackup'): backup = False cl = repo.changelog revs = list(revs) + opts.get('rev') revs = set(scmutil.revrange(repo, revs)) with repo.wlock(): bookmarks = set(opts.get('bookmark')) if bookmarks: repomarks = repo._bookmarks if not bookmarks.issubset(repomarks): raise error.Abort(_("bookmark '%s' not found") % ','.join(sorted(bookmarks - set(repomarks.keys())))) # If the requested bookmark is not the only one pointing to a # a revision we have to only delete the bookmark and not strip # anything. revsets cannot detect that case. nodetobookmarks = {} for mark, node in repomarks.iteritems(): nodetobookmarks.setdefault(node, []).append(mark) for marks in nodetobookmarks.values(): if bookmarks.issuperset(marks): rsrevs = repair.stripbmrevset(repo, marks[0]) revs.update(set(rsrevs)) if not revs: lock = tr = None try: lock = repo.lock() tr = repo.transaction('bookmark') for bookmark in bookmarks: del repomarks[bookmark] repomarks.recordchange(tr) tr.close() for bookmark in sorted(bookmarks): ui.write(_("bookmark '%s' deleted\n") % bookmark) finally: release(lock, tr) if not revs: raise error.Abort(_('empty revision set')) descendants = set(cl.descendants(revs)) strippedrevs = revs.union(descendants) roots = revs.difference(descendants) update = False # if one of the wdir parent is stripped we'll need # to update away to an earlier revision for p in repo.dirstate.parents(): if p != nullid and cl.rev(p) in strippedrevs: update = True break rootnodes = set(cl.node(r) for r in roots) q = getattr(repo, 'mq', None) if q is not None and q.applied: # refresh queue state if we're about to strip # applied patches if cl.rev(repo.lookup('qtip')) in strippedrevs: q.applieddirty = True start = 0 end = len(q.applied) for i, statusentry in enumerate(q.applied): if statusentry.node in rootnodes: # if one of the stripped roots is an applied # patch, only part of the queue is stripped start = i break del q.applied[start:end] q.savedirty() revs = sorted(rootnodes) if update and opts.get('keep'): urev, p2 = repo.changelog.parents(revs[0]) if (util.safehasattr(repo, 'mq') and p2 != nullid and p2 in [x.node for x in repo.mq.applied]): urev = p2 uctx = repo[urev] # only reset the dirstate for files that would actually change # between the working context and uctx descendantrevs = repo.revs("%s::." % uctx.rev()) changedfiles = [] for rev in descendantrevs: # blindly reset the files, regardless of what actually changed changedfiles.extend(repo[rev].files()) # reset files that only changed in the dirstate too dirstate = repo.dirstate dirchanges = [f for f in dirstate if dirstate[f] != 'n'] changedfiles.extend(dirchanges) repo.dirstate.rebuild(urev, uctx.manifest(), changedfiles) repo.dirstate.write(repo.currenttransaction()) # clear resolve state merge.mergestate.clean(repo, repo['.'].node()) update = False strip(ui, repo, revs, backup=backup, update=update, force=opts.get('force'), bookmarks=bookmarks) return 0