Mercurial > hg
view hgext/pager.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 | bd55d98027ee |
children | 39d13b8c101d |
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# pager.py - display output using a pager # # Copyright 2008 David Soria Parra <dsp@php.net> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. # # To load the extension, add it to your configuration file: # # [extension] # pager = # # Run 'hg help pager' to get info on configuration. '''browse command output with an external pager To set the pager that should be used, set the application variable:: [pager] pager = less -FRX If no pager is set, the pager extensions uses the environment variable $PAGER. If neither pager.pager, nor $PAGER is set, no pager is used. You can disable the pager for certain commands by adding them to the pager.ignore list:: [pager] ignore = version, help, update You can also enable the pager only for certain commands using pager.attend. Below is the default list of commands to be paged:: [pager] attend = annotate, cat, diff, export, glog, log, qdiff Setting pager.attend to an empty value will cause all commands to be paged. If pager.attend is present, pager.ignore will be ignored. Lastly, you can enable and disable paging for individual commands with the attend-<command> option. This setting takes precedence over existing attend and ignore options and defaults:: [pager] attend-cat = false To ignore global commands like :hg:`version` or :hg:`help`, you have to specify them in your user configuration file. To control whether the pager is used at all for an individual command, you can use --pager=<value>:: - use as needed: `auto`. - require the pager: `yes` or `on`. - suppress the pager: `no` or `off` (any unrecognized value will also work). ''' from __future__ import absolute_import import atexit import os import signal import subprocess import sys from mercurial.i18n import _ from mercurial import ( cmdutil, commands, dispatch, extensions, util, ) # 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 _runpager(ui, p): pager = subprocess.Popen(p, shell=True, bufsize=-1, close_fds=util.closefds, stdin=subprocess.PIPE, stdout=sys.stdout, stderr=sys.stderr) # back up original file objects and descriptors olduifout = ui.fout oldstdout = sys.stdout stdoutfd = os.dup(sys.stdout.fileno()) stderrfd = os.dup(sys.stderr.fileno()) # create new line-buffered stdout so that output can show up immediately ui.fout = sys.stdout = newstdout = os.fdopen(sys.stdout.fileno(), 'wb', 1) os.dup2(pager.stdin.fileno(), sys.stdout.fileno()) if ui._isatty(sys.stderr): os.dup2(pager.stdin.fileno(), sys.stderr.fileno()) @atexit.register def killpager(): if util.safehasattr(signal, "SIGINT"): signal.signal(signal.SIGINT, signal.SIG_IGN) pager.stdin.close() ui.fout = olduifout sys.stdout = oldstdout # close new stdout while it's associated with pager; otherwise stdout # fd would be closed when newstdout is deleted newstdout.close() # restore original fds: stdout is open again os.dup2(stdoutfd, sys.stdout.fileno()) os.dup2(stderrfd, sys.stderr.fileno()) pager.wait() def uisetup(ui): if '--debugger' in sys.argv or not ui.formatted(): return # chg has its own pager implementation argv = sys.argv[:] if 'chgunix' in dispatch._earlygetopt(['--cmdserver'], argv): return def pagecmd(orig, ui, options, cmd, cmdfunc): p = ui.config("pager", "pager", os.environ.get("PAGER")) usepager = False always = util.parsebool(options['pager']) auto = options['pager'] == 'auto' if not p: pass elif always: usepager = True elif not auto: usepager = False else: attend = ui.configlist('pager', 'attend', attended) ignore = ui.configlist('pager', 'ignore') cmds, _ = cmdutil.findcmd(cmd, commands.table) for cmd in cmds: var = 'attend-%s' % cmd if ui.config('pager', var): usepager = ui.configbool('pager', var) break if (cmd in attend or (cmd not in ignore and not attend)): usepager = True break setattr(ui, 'pageractive', usepager) if usepager: ui.setconfig('ui', 'formatted', ui.formatted(), 'pager') ui.setconfig('ui', 'interactive', False, 'pager') if util.safehasattr(signal, "SIGPIPE"): signal.signal(signal.SIGPIPE, signal.SIG_DFL) _runpager(ui, p) return orig(ui, options, cmd, cmdfunc) # Wrap dispatch._runcommand after color is loaded so color can see # ui.pageractive. Otherwise, if we loaded first, color's wrapped # dispatch._runcommand would run without having access to ui.pageractive. def afterloaded(loaded): extensions.wrapfunction(dispatch, '_runcommand', pagecmd) extensions.afterloaded('color', afterloaded) def extsetup(ui): commands.globalopts.append( ('', 'pager', 'auto', _("when to paginate (boolean, always, auto, or never)"), _('TYPE'))) attended = ['annotate', 'cat', 'diff', 'export', 'glog', 'log', 'qdiff']