Mercurial > hg
view hgext/hgk.py @ 26380:56a640b0f656
revlog: don't flush data file after every added revision
The current behavior of revlogs is to flush the data file when writing
data to it. Tracing system calls revealed that changegroup processing
incurred numerous write(2) calls for values much smaller than the
default buffer size (Python defaults to 4096, but it can be adjusted
based on detected block size at run time by CPython).
The reason we flush revlogs is so readers have all data available.
For example, the current code in revlog.py will re-open the revlog
file (instead of seeking an existing file handle) to read the text
of a revision. This happens when starting a new delta chain when
adding several revisions from changegroups, for example. Yes, this
is likely sub-optimal (we should probably be sharing file descriptors
between readers and writers to avoid the flushing and associated
overhead of re-opening files).
While flushing revlogs is necessary, it appears all callers are
diligent about flushing files before a read is performed (see
buildtext() in _addrevision()), making the flush in
_writeentry() redundant and unncessary. So, we remove it. In practice,
this means we incur a write(2) a) when the buffer is full (typically
4096 bytes) b) when a new delta chain is created rather than after
every added revision. This applies to every revlog, but by volume
it mostly impacts filelogs.
Removing the redundant flush from _writeentry() significantly
reduces the number of write(2) calls during changegroup processing on
my Linux machine. When applying a changegroup of the hg repo based on
my local repo, the total number of write(2) calls during application
of the mercurial/localrepo.py revlogs dropped from 1,320 to 217 with
this patch applied. Total I/O related system calls dropped from 1,577
to 474.
When unbundling a mozilla-central gzipped bundle (264,403 changesets
with 1,492,215 changes to 222,507 files), total write(2) calls
dropped from 1,252,881 to 827,106 and total system calls dropped from
3,601,259 to 3,178,636 - a reduction of 425,775!
While the system call reduction is significant, it appears
to have no impact on wall time on my Linux and Windows machines. Still,
fewer syscalls is fewer syscalls. Surely this can't hurt. If nothing
else, it makes examining remaining system call usage simpler and opens
the door to experimenting with the performance impact of different
buffer sizes.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 26 Sep 2015 21:43:13 -0700 |
parents | 084957666642 |
children | 9b12517a7081 |
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# Minimal support for git commands on an hg repository # # Copyright 2005, 2006 Chris Mason <mason@suse.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. '''browse the repository in a graphical way The hgk extension allows browsing the history of a repository in a graphical way. It requires Tcl/Tk version 8.4 or later. (Tcl/Tk is not distributed with Mercurial.) hgk consists of two parts: a Tcl script that does the displaying and querying of information, and an extension to Mercurial named hgk.py, which provides hooks for hgk to get information. hgk can be found in the contrib directory, and the extension is shipped in the hgext repository, and needs to be enabled. The :hg:`view` command will launch the hgk Tcl script. For this command to work, hgk must be in your search path. Alternately, you can specify the path to hgk in your configuration file:: [hgk] path = /location/of/hgk hgk can make use of the extdiff extension to visualize revisions. Assuming you had already configured extdiff vdiff command, just add:: [hgk] vdiff=vdiff Revisions context menu will now display additional entries to fire vdiff on hovered and selected revisions. ''' import os from mercurial import cmdutil, commands, patch, scmutil, obsolete from mercurial.node import nullid, nullrev, short from mercurial.i18n import _ cmdtable = {} command = cmdutil.command(cmdtable) # Note for extension authors: ONLY specify testedwith = 'internal' 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 = 'internal' @command('debug-diff-tree', [('p', 'patch', None, _('generate patch')), ('r', 'recursive', None, _('recursive')), ('P', 'pretty', None, _('pretty')), ('s', 'stdin', None, _('stdin')), ('C', 'copy', None, _('detect copies')), ('S', 'search', "", _('search'))], ('[OPTION]... NODE1 NODE2 [FILE]...'), inferrepo=True) def difftree(ui, repo, node1=None, node2=None, *files, **opts): """diff trees from two commits""" def __difftree(repo, node1, node2, files=[]): assert node2 is not None mmap = repo[node1].manifest() mmap2 = repo[node2].manifest() m = scmutil.match(repo[node1], files) modified, added, removed = repo.status(node1, node2, m)[:3] empty = short(nullid) for f in modified: # TODO get file permissions ui.write(":100664 100664 %s %s M\t%s\t%s\n" % (short(mmap[f]), short(mmap2[f]), f, f)) for f in added: ui.write(":000000 100664 %s %s N\t%s\t%s\n" % (empty, short(mmap2[f]), f, f)) for f in removed: ui.write(":100664 000000 %s %s D\t%s\t%s\n" % (short(mmap[f]), empty, f, f)) ## while True: if opts['stdin']: try: line = raw_input().split(' ') node1 = line[0] if len(line) > 1: node2 = line[1] else: node2 = None except EOFError: break node1 = repo.lookup(node1) if node2: node2 = repo.lookup(node2) else: node2 = node1 node1 = repo.changelog.parents(node1)[0] if opts['patch']: if opts['pretty']: catcommit(ui, repo, node2, "") m = scmutil.match(repo[node1], files) diffopts = patch.difffeatureopts(ui) diffopts.git = True chunks = patch.diff(repo, node1, node2, match=m, opts=diffopts) for chunk in chunks: ui.write(chunk) else: __difftree(repo, node1, node2, files=files) if not opts['stdin']: break def catcommit(ui, repo, n, prefix, ctx=None): nlprefix = '\n' + prefix if ctx is None: ctx = repo[n] # use ctx.node() instead ?? ui.write(("tree %s\n" % short(ctx.changeset()[0]))) for p in ctx.parents(): ui.write(("parent %s\n" % p)) date = ctx.date() description = ctx.description().replace("\0", "") ui.write(("author %s %s %s\n" % (ctx.user(), int(date[0]), date[1]))) if 'committer' in ctx.extra(): ui.write(("committer %s\n" % ctx.extra()['committer'])) ui.write(("revision %d\n" % ctx.rev())) ui.write(("branch %s\n" % ctx.branch())) if obsolete.isenabled(repo, obsolete.createmarkersopt): if ctx.obsolete(): ui.write(("obsolete\n")) ui.write(("phase %s\n\n" % ctx.phasestr())) if prefix != "": ui.write("%s%s\n" % (prefix, description.replace('\n', nlprefix).strip())) else: ui.write(description + "\n") if prefix: ui.write('\0') @command('debug-merge-base', [], _('REV REV')) def base(ui, repo, node1, node2): """output common ancestor information""" node1 = repo.lookup(node1) node2 = repo.lookup(node2) n = repo.changelog.ancestor(node1, node2) ui.write(short(n) + "\n") @command('debug-cat-file', [('s', 'stdin', None, _('stdin'))], _('[OPTION]... TYPE FILE'), inferrepo=True) def catfile(ui, repo, type=None, r=None, **opts): """cat a specific revision""" # in stdin mode, every line except the commit is prefixed with two # spaces. This way the our caller can find the commit without magic # strings # prefix = "" if opts['stdin']: try: (type, r) = raw_input().split(' ') prefix = " " except EOFError: return else: if not type or not r: ui.warn(_("cat-file: type or revision not supplied\n")) commands.help_(ui, 'cat-file') while r: if type != "commit": ui.warn(_("aborting hg cat-file only understands commits\n")) return 1 n = repo.lookup(r) catcommit(ui, repo, n, prefix) if opts['stdin']: try: (type, r) = raw_input().split(' ') except EOFError: break else: break # git rev-tree is a confusing thing. You can supply a number of # commit sha1s on the command line, and it walks the commit history # telling you which commits are reachable from the supplied ones via # a bitmask based on arg position. # you can specify a commit to stop at by starting the sha1 with ^ def revtree(ui, args, repo, full="tree", maxnr=0, parents=False): def chlogwalk(): count = len(repo) i = count l = [0] * 100 chunk = 100 while True: if chunk > i: chunk = i i = 0 else: i -= chunk for x in xrange(chunk): if i + x >= count: l[chunk - x:] = [0] * (chunk - x) break if full is not None: if (i + x) in repo: l[x] = repo[i + x] l[x].changeset() # force reading else: if (i + x) in repo: l[x] = 1 for x in xrange(chunk - 1, -1, -1): if l[x] != 0: yield (i + x, full is not None and l[x] or None) if i == 0: break # calculate and return the reachability bitmask for sha def is_reachable(ar, reachable, sha): if len(ar) == 0: return 1 mask = 0 for i in xrange(len(ar)): if sha in reachable[i]: mask |= 1 << i return mask reachable = [] stop_sha1 = [] want_sha1 = [] count = 0 # figure out which commits they are asking for and which ones they # want us to stop on for i, arg in enumerate(args): if arg.startswith('^'): s = repo.lookup(arg[1:]) stop_sha1.append(s) want_sha1.append(s) elif arg != 'HEAD': want_sha1.append(repo.lookup(arg)) # calculate the graph for the supplied commits for i, n in enumerate(want_sha1): reachable.append(set()) visit = [n] reachable[i].add(n) while visit: n = visit.pop(0) if n in stop_sha1: continue for p in repo.changelog.parents(n): if p not in reachable[i]: reachable[i].add(p) visit.append(p) if p in stop_sha1: continue # walk the repository looking for commits that are in our # reachability graph for i, ctx in chlogwalk(): if i not in repo: continue n = repo.changelog.node(i) mask = is_reachable(want_sha1, reachable, n) if mask: parentstr = "" if parents: pp = repo.changelog.parents(n) if pp[0] != nullid: parentstr += " " + short(pp[0]) if pp[1] != nullid: parentstr += " " + short(pp[1]) if not full: ui.write("%s%s\n" % (short(n), parentstr)) elif full == "commit": ui.write("%s%s\n" % (short(n), parentstr)) catcommit(ui, repo, n, ' ', ctx) else: (p1, p2) = repo.changelog.parents(n) (h, h1, h2) = map(short, (n, p1, p2)) (i1, i2) = map(repo.changelog.rev, (p1, p2)) date = ctx.date()[0] ui.write("%s %s:%s" % (date, h, mask)) mask = is_reachable(want_sha1, reachable, p1) if i1 != nullrev and mask > 0: ui.write("%s:%s " % (h1, mask)), mask = is_reachable(want_sha1, reachable, p2) if i2 != nullrev and mask > 0: ui.write("%s:%s " % (h2, mask)) ui.write("\n") if maxnr and count >= maxnr: break count += 1 # git rev-list tries to order things by date, and has the ability to stop # at a given commit without walking the whole repo. TODO add the stop # parameter @command('debug-rev-list', [('H', 'header', None, _('header')), ('t', 'topo-order', None, _('topo-order')), ('p', 'parents', None, _('parents')), ('n', 'max-count', 0, _('max-count'))], ('[OPTION]... REV...')) def revlist(ui, repo, *revs, **opts): """print revisions""" if opts['header']: full = "commit" else: full = None copy = [x for x in revs] revtree(ui, copy, repo, full, opts['max_count'], opts['parents']) @command('view', [('l', 'limit', '', _('limit number of changes displayed'), _('NUM'))], _('[-l LIMIT] [REVRANGE]')) def view(ui, repo, *etc, **opts): "start interactive history viewer" os.chdir(repo.root) optstr = ' '.join(['--%s %s' % (k, v) for k, v in opts.iteritems() if v]) if repo.filtername is None: optstr += '--hidden' cmd = ui.config("hgk", "path", "hgk") + " %s %s" % (optstr, " ".join(etc)) ui.debug("running %s\n" % cmd) ui.system(cmd)