Mercurial > hg
view contrib/hgperf @ 27430:e240e914d226 stable
revlog: seek to end of file before writing (issue4943)
Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.
Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.
The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.
Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.
This patch appears to have little to no impact on performance on my
Linux machine.
author | Gregory Szorc <gregory.szorc@gmail.com> |
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date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | 377a111d1cd2 |
children | 22fbca1d11ed |
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#!/usr/bin/env python # # hgperf - measure performance of Mercurial commands # # Copyright 2014 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. '''measure performance of Mercurial commands Using ``hgperf`` instead of ``hg`` measures performance of the target Mercurial command. For example, the execution below measures performance of :hg:`heads --topo`:: $ hgperf heads --topo All command output via ``ui`` is suppressed, and just measurement result is displayed: see also "perf" extension in "contrib". Costs of processing before dispatching to the command function like below are not measured:: - parsing command line (e.g. option validity check) - reading configuration files in But ``pre-`` and ``post-`` hook invocation for the target command is measured, even though these are invoked before or after dispatching to the command function, because these may be required to repeat execution of the target command correctly. ''' import os import sys libdir = '@LIBDIR@' if libdir != '@' 'LIBDIR' '@': if not os.path.isabs(libdir): libdir = os.path.join(os.path.dirname(os.path.realpath(__file__)), libdir) libdir = os.path.abspath(libdir) sys.path.insert(0, libdir) # enable importing on demand to reduce startup time try: from mercurial import demandimport; demandimport.enable() except ImportError: import sys sys.stderr.write("abort: couldn't find mercurial libraries in [%s]\n" % ' '.join(sys.path)) sys.stderr.write("(check your install and PYTHONPATH)\n") sys.exit(-1) import mercurial.util import mercurial.dispatch import time def timer(func, title=None): results = [] begin = time.time() count = 0 while True: ostart = os.times() cstart = time.time() r = func() cstop = time.time() ostop = os.times() count += 1 a, b = ostart, ostop results.append((cstop - cstart, b[0] - a[0], b[1]-a[1])) if cstop - begin > 3 and count >= 100: break if cstop - begin > 10 and count >= 3: break if title: sys.stderr.write("! %s\n" % title) if r: sys.stderr.write("! result: %s\n" % r) m = min(results) sys.stderr.write("! wall %f comb %f user %f sys %f (best of %d)\n" % (m[0], m[1] + m[2], m[1], m[2], count)) orgruncommand = mercurial.dispatch.runcommand def runcommand(lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions): ui.pushbuffer() lui.pushbuffer() timer(lambda : orgruncommand(lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions)) ui.popbuffer() lui.popbuffer() mercurial.dispatch.runcommand = runcommand for fp in (sys.stdin, sys.stdout, sys.stderr): mercurial.util.setbinary(fp) mercurial.dispatch.run()