perf: add threading capability to perfbdiff
Since we are releasing the GIL during diffing, it is interesting to see how a
thread pool would perform on diffing. We add a new `--threads` argument to
commands. Synchronizing the thread pool is a bit complex because we want to be
able to reuse it from one run to another.
On my computer (i7 with 4 cores + hyperthreading), I get the following data for
about 12000 revisions:
threads wall comb wall gain comb overhead
none 31.596715 31.59 0.00% 0.00%
1 31.621228 31.62 -0.08% 0.09%
2 16.406202 32.8 48.08% 3.83%
3 11.598334 34.76 63.29% 10.03%
4 9.205421 36.77 70.87% 16.40%
5 8.517604 42.51 73.04% 34.57%
6 7.94645 47.58 74.85% 50.62%
7 7.434972 51.92 76.47% 64.36%
8 7.070638 55.34 77.62% 75.18%
Compared to the feature disabled (threads=0), the overhead is negligible with
the threading code (threads=1), and the gain is already 48% with two threads.
#!/usr/bin/env python
#
# runrst - register custom roles and run correct writer
#
# Copyright 2010 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""usage: %s WRITER args...
where WRITER is the name of a Docutils writer such as 'html' or 'manpage'
"""
import sys
try:
from docutils.parsers.rst import roles
from docutils.core import publish_cmdline
from docutils import nodes, utils
except ImportError:
sys.stderr.write("abort: couldn't generate documentation: docutils "
"module is missing\n")
sys.stderr.write("please install python-docutils or see "
"http://docutils.sourceforge.net/\n")
sys.exit(-1)
def role_hg(name, rawtext, text, lineno, inliner,
options={}, content=[]):
text = "hg " + utils.unescape(text)
linktext = nodes.literal(rawtext, text)
parts = text.split()
cmd, args = parts[1], parts[2:]
refuri = "hg.1.html#%s" % cmd
if cmd == 'help' and args:
if args[0] == 'config':
# :hg:`help config`
refuri = "hgrc.5.html"
elif args[0].startswith('config.'):
# :hg:`help config.SECTION...`
refuri = "hgrc.5.html#%s" % args[0].split('.', 2)[1]
elif len(args) >= 2 and args[0] == '-c':
# :hg:`help -c COMMAND ...` is equivalent to :hg:`COMMAND`
# (mainly for :hg:`help -c config`)
refuri = "hg.1.html#%s" % args[1]
else:
refuri = "hg.1.html#%s" % args[0]
node = nodes.reference(rawtext, '', linktext,
refuri=refuri)
return [node], []
roles.register_local_role("hg", role_hg)
if __name__ == "__main__":
if len(sys.argv) < 2:
sys.stderr.write(__doc__ % sys.argv[0])
sys.exit(1)
writer = sys.argv[1]
del sys.argv[1]
publish_cmdline(writer_name=writer)