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
from __future__ import absolute_import
"""
Small and dumb HTTP server for use in tests.
"""
import optparse
import os
import signal
import socket
import sys
from mercurial import (
server,
util,
)
httpserver = util.httpserver
OptionParser = optparse.OptionParser
if os.environ.get('HGIPV6', '0') == '1':
class simplehttpserver(httpserver.httpserver):
address_family = socket.AF_INET6
else:
simplehttpserver = httpserver.httpserver
class _httprequesthandler(httpserver.simplehttprequesthandler):
def log_message(self, format, *args):
httpserver.simplehttprequesthandler.log_message(self, format, *args)
sys.stderr.flush()
class simplehttpservice(object):
def __init__(self, host, port):
self.address = (host, port)
def init(self):
self.httpd = simplehttpserver(self.address, _httprequesthandler)
def run(self):
self.httpd.serve_forever()
if __name__ == '__main__':
parser = OptionParser()
parser.add_option('-p', '--port', dest='port', type='int', default=8000,
help='TCP port to listen on', metavar='PORT')
parser.add_option('-H', '--host', dest='host', default='localhost',
help='hostname or IP to listen on', metavar='HOST')
parser.add_option('--logfile', help='file name of access/error log')
parser.add_option('--pid', dest='pid',
help='file name where the PID of the server is stored')
parser.add_option('-f', '--foreground', dest='foreground',
action='store_true',
help='do not start the HTTP server in the background')
parser.add_option('--daemon-postexec', action='append')
(options, args) = parser.parse_args()
signal.signal(signal.SIGTERM, lambda x, y: sys.exit(0))
if options.foreground and options.logfile:
parser.error("options --logfile and --foreground are mutually "
"exclusive")
if options.foreground and options.pid:
parser.error("options --pid and --foreground are mutually exclusive")
opts = {'pid_file': options.pid,
'daemon': not options.foreground,
'daemon_postexec': options.daemon_postexec}
service = simplehttpservice(options.host, options.port)
server.runservice(opts, initfn=service.init, runfn=service.run,
logfile=options.logfile,
runargs=[sys.executable, __file__] + sys.argv[1:])