Mercurial > hg
view mercurial/destutil.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 | 40f845537dca |
children | 318a24b52eeb |
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# destutil.py - Mercurial utility function for command destination # # Copyright Matt Mackall <mpm@selenic.com> and other # # 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 from .i18n import _ from . import ( bookmarks, error, obsolete, ) def _destupdatevalidate(repo, rev, clean, check): """validate that the destination comply to various rules This exists as its own function to help wrapping from extensions.""" wc = repo[None] p1 = wc.p1() if not clean: # Check that the update is linear. # # Mercurial do not allow update-merge for non linear pattern # (that would be technically possible but was considered too confusing # for user a long time ago) # # See mercurial.merge.update for details if p1.rev() not in repo.changelog.ancestors([rev], inclusive=True): dirty = wc.dirty(missing=True) foreground = obsolete.foreground(repo, [p1.node()]) if not repo[rev].node() in foreground: if dirty: msg = _("uncommitted changes") hint = _("commit and merge, or update --clean to" " discard changes") raise error.UpdateAbort(msg, hint=hint) elif not check: # destination is not a descendant. msg = _("not a linear update") hint = _("merge or update --check to force update") raise error.UpdateAbort(msg, hint=hint) def _destupdateobs(repo, clean, check): """decide of an update destination from obsolescence markers""" node = None wc = repo[None] p1 = wc.p1() movemark = None if p1.obsolete() and not p1.children(): # allow updating to successors successors = obsolete.successorssets(repo, p1.node()) # behavior of certain cases is as follows, # # divergent changesets: update to highest rev, similar to what # is currently done when there are more than one head # (i.e. 'tip') # # replaced changesets: same as divergent except we know there # is no conflict # # pruned changeset: no update is done; though, we could # consider updating to the first non-obsolete parent, # similar to what is current done for 'hg prune' if successors: # flatten the list here handles both divergent (len > 1) # and the usual case (len = 1) successors = [n for sub in successors for n in sub] # get the max revision for the given successors set, # i.e. the 'tip' of a set node = repo.revs('max(%ln)', successors).first() if bookmarks.isactivewdirparent(repo): movemark = repo['.'].node() return node, movemark, None def _destupdatebook(repo, clean, check): """decide on an update destination from active bookmark""" # we also move the active bookmark, if any activemark = None node, movemark = bookmarks.calculateupdate(repo.ui, repo, None) if node is not None: activemark = node return node, movemark, activemark def _destupdatebranch(repo, clean, check): """decide on an update destination from current branch This ignores closed branch heads. """ wc = repo[None] movemark = node = None currentbranch = wc.branch() if clean: currentbranch = repo['.'].branch() if currentbranch in repo.branchmap(): heads = repo.branchheads(currentbranch) if heads: node = repo.revs('max(.::(%ln))', heads).first() if bookmarks.isactivewdirparent(repo): movemark = repo['.'].node() elif currentbranch == 'default' and not wc.p1(): # "null" parent belongs to "default" branch, but it doesn't exist, so # update to the tipmost non-closed branch head node = repo.revs('max(head() and not closed())').first() else: node = repo['.'].node() return node, movemark, None def _destupdatebranchfallback(repo, clean, check): """decide on an update destination from closed heads in current branch""" wc = repo[None] currentbranch = wc.branch() movemark = None if currentbranch in repo.branchmap(): # here, all descendant branch heads are closed heads = repo.branchheads(currentbranch, closed=True) assert heads, "any branch has at least one head" node = repo.revs('max(.::(%ln))', heads).first() assert node is not None, ("any revision has at least " "one descendant branch head") if bookmarks.isactivewdirparent(repo): movemark = repo['.'].node() else: # here, no "default" branch, and all branches are closed node = repo.lookup('tip') assert node is not None, "'tip' exists even in empty repository" return node, movemark, None # order in which each step should be evalutated # steps are run until one finds a destination destupdatesteps = ['evolution', 'bookmark', 'branch', 'branchfallback'] # mapping to ease extension overriding steps. destupdatestepmap = {'evolution': _destupdateobs, 'bookmark': _destupdatebook, 'branch': _destupdatebranch, 'branchfallback': _destupdatebranchfallback, } def destupdate(repo, clean=False, check=False): """destination for bare update operation return (rev, movemark, activemark) - rev: the revision to update to, - movemark: node to move the active bookmark from (cf bookmark.calculate update), - activemark: a bookmark to activate at the end of the update. """ node = movemark = activemark = None for step in destupdatesteps: node, movemark, activemark = destupdatestepmap[step](repo, clean, check) if node is not None: break rev = repo[node].rev() _destupdatevalidate(repo, rev, clean, check) return rev, movemark, activemark msgdestmerge = { # too many matching divergent bookmark 'toomanybookmarks': {'merge': (_("multiple matching bookmarks to merge -" " please merge with an explicit rev or bookmark"), _("run 'hg heads' to see all heads")), 'rebase': (_("multiple matching bookmarks to rebase -" " please rebase to an explicit rev or bookmark"), _("run 'hg heads' to see all heads")), }, # no other matching divergent bookmark 'nootherbookmarks': {'merge': (_("no matching bookmark to merge - " "please merge with an explicit rev or bookmark"), _("run 'hg heads' to see all heads")), 'rebase': (_("no matching bookmark to rebase - " "please rebase to an explicit rev or bookmark"), _("run 'hg heads' to see all heads")), }, # branch have too many unbookmarked heads, no obvious destination 'toomanyheads': {'merge': (_("branch '%s' has %d heads - please merge with an explicit rev"), _("run 'hg heads .' to see heads")), 'rebase': (_("branch '%s' has %d heads - please rebase to an explicit rev"), _("run 'hg heads .' to see heads")), }, # branch have no other unbookmarked heads 'bookmarkedheads': {'merge': (_("heads are bookmarked - please merge with an explicit rev"), _("run 'hg heads' to see all heads")), 'rebase': (_("heads are bookmarked - please rebase to an explicit rev"), _("run 'hg heads' to see all heads")), }, # branch have just a single heads, but there is other branches 'nootherbranchheads': {'merge': (_("branch '%s' has one head - please merge with an explicit rev"), _("run 'hg heads' to see all heads")), 'rebase': (_("branch '%s' has one head - please rebase to an explicit rev"), _("run 'hg heads' to see all heads")), }, # repository have a single head 'nootherheads': {'merge': (_('nothing to merge'), None), 'rebase': (_('nothing to rebase'), None), }, # repository have a single head and we are not on it 'nootherheadsbehind': {'merge': (_('nothing to merge'), _("use 'hg update' instead")), 'rebase': (_('nothing to rebase'), _("use 'hg update' instead")), }, # We are not on a head 'notatheads': {'merge': (_('working directory not at a head revision'), _("use 'hg update' or merge with an explicit revision")), 'rebase': (_('working directory not at a head revision'), _("use 'hg update' or rebase to an explicit revision")) }, 'emptysourceset': {'merge': (_('source set is empty'), None), 'rebase': (_('source set is empty'), None), }, 'multiplebranchessourceset': {'merge': (_('source set is rooted in multiple branches'), None), 'rebase': (_('rebaseset is rooted in multiple named branches'), _('specify an explicit destination with --dest')), }, } def _destmergebook(repo, action='merge', sourceset=None, destspace=None): """find merge destination in the active bookmark case""" node = None bmheads = repo.bookmarkheads(repo._activebookmark) curhead = repo[repo._activebookmark].node() if len(bmheads) == 2: if curhead == bmheads[0]: node = bmheads[1] else: node = bmheads[0] elif len(bmheads) > 2: msg, hint = msgdestmerge['toomanybookmarks'][action] raise error.ManyMergeDestAbort(msg, hint=hint) elif len(bmheads) <= 1: msg, hint = msgdestmerge['nootherbookmarks'][action] raise error.NoMergeDestAbort(msg, hint=hint) assert node is not None return node def _destmergebranch(repo, action='merge', sourceset=None, onheadcheck=True, destspace=None): """find merge destination based on branch heads""" node = None if sourceset is None: sourceset = [repo[repo.dirstate.p1()].rev()] branch = repo.dirstate.branch() elif not sourceset: msg, hint = msgdestmerge['emptysourceset'][action] raise error.NoMergeDestAbort(msg, hint=hint) else: branch = None for ctx in repo.set('roots(%ld::%ld)', sourceset, sourceset): if branch is not None and ctx.branch() != branch: msg, hint = msgdestmerge['multiplebranchessourceset'][action] raise error.ManyMergeDestAbort(msg, hint=hint) branch = ctx.branch() bheads = repo.branchheads(branch) onhead = repo.revs('%ld and %ln', sourceset, bheads) if onheadcheck and not onhead: # Case A: working copy if not on a head. (merge only) # # This is probably a user mistake We bailout pointing at 'hg update' if len(repo.heads()) <= 1: msg, hint = msgdestmerge['nootherheadsbehind'][action] else: msg, hint = msgdestmerge['notatheads'][action] raise error.Abort(msg, hint=hint) # remove heads descendants of source from the set bheads = list(repo.revs('%ln - (%ld::)', bheads, sourceset)) # filters out bookmarked heads nbhs = list(repo.revs('%ld - bookmark()', bheads)) if destspace is not None: # restrict search space # used in the 'hg pull --rebase' case, see issue 5214. nbhs = list(repo.revs('%ld and %ld', destspace, nbhs)) if len(nbhs) > 1: # Case B: There is more than 1 other anonymous heads # # This means that there will be more than 1 candidate. This is # ambiguous. We abort asking the user to pick as explicit destination # instead. msg, hint = msgdestmerge['toomanyheads'][action] msg %= (branch, len(bheads) + 1) raise error.ManyMergeDestAbort(msg, hint=hint) elif not nbhs: # Case B: There is no other anonymous heads # # This means that there is no natural candidate to merge with. # We abort, with various messages for various cases. if bheads: msg, hint = msgdestmerge['bookmarkedheads'][action] elif len(repo.heads()) > 1: msg, hint = msgdestmerge['nootherbranchheads'][action] msg %= branch elif not onhead: # if 'onheadcheck == False' (rebase case), # this was not caught in Case A. msg, hint = msgdestmerge['nootherheadsbehind'][action] else: msg, hint = msgdestmerge['nootherheads'][action] raise error.NoMergeDestAbort(msg, hint=hint) else: node = nbhs[0] assert node is not None return node def destmerge(repo, action='merge', sourceset=None, onheadcheck=True, destspace=None): """return the default destination for a merge (or raise exception about why it can't pick one) :action: the action being performed, controls emitted error message """ # destspace is here to work around issues with `hg pull --rebase` see # issue5214 for details if repo._activebookmark: node = _destmergebook(repo, action=action, sourceset=sourceset, destspace=destspace) else: node = _destmergebranch(repo, action=action, sourceset=sourceset, onheadcheck=onheadcheck, destspace=destspace) return repo[node].rev() histeditdefaultrevset = 'reverse(only(.) and not public() and not ::merge())' def desthistedit(ui, repo): """Default base revision to edit for `hg histedit`.""" # Avoid cycle: scmutil -> revset -> destutil from . import scmutil default = ui.config('histedit', 'defaultrev', histeditdefaultrevset) if default: revs = scmutil.revrange(repo, [default]) if revs: # The revset supplied by the user may not be in ascending order nor # take the first revision. So do this manually. revs.sort() return revs.first() return None def _statusotherbook(ui, repo): bmheads = repo.bookmarkheads(repo._activebookmark) curhead = repo[repo._activebookmark].node() if repo.revs('%n and parents()', curhead): # we are on the active bookmark bmheads = [b for b in bmheads if curhead != b] if bmheads: msg = _('%i other divergent bookmarks for "%s"\n') ui.status(msg % (len(bmheads), repo._activebookmark)) def _statusotherbranchheads(ui, repo): currentbranch = repo.dirstate.branch() allheads = repo.branchheads(currentbranch, closed=True) heads = repo.branchheads(currentbranch) if repo.revs('%ln and parents()', allheads): # we are on a head, even though it might be closed # # on closed otherheads # ========= ========== # o 0 all heads for current branch are closed # N only descendant branch heads are closed # x 0 there is only one non-closed branch head # N there are some non-closed branch heads # ========= ========== otherheads = repo.revs('%ln - parents()', heads) if repo['.'].closesbranch(): ui.warn(_('no open descendant heads on branch "%s", ' 'updating to a closed head\n') % (currentbranch)) if otherheads: ui.warn(_("(committing will reopen the head, " "use 'hg heads .' to see %i other heads)\n") % (len(otherheads))) else: ui.warn(_('(committing will reopen branch "%s")\n') % (currentbranch)) elif otherheads: ui.status(_('%i other heads for branch "%s"\n') % (len(otherheads), currentbranch)) def statusotherdests(ui, repo): """Print message about other head""" # XXX we should probably include a hint: # - about what to do # - how to see such heads if repo._activebookmark: _statusotherbook(ui, repo) else: _statusotherbranchheads(ui, repo)