util.chunkbuffer: avoid extra mutations when reading partial chunks
Previously, a read(N) where N was less than the length of the first
available chunk would mutate the deque instance twice and allocate a new
str from the slice of the existing chunk. Profiling drawed my attention
to these as a potential hot spot during changegroup reading.
This patch makes the code more complicated in order to avoid the
aforementioned 3 operations.
On a pre-generated mozilla-central gzip bundle, this series has the
following impact on `hg unbundle` performance on my MacBook Pro:
before: 358.21 real 317.69 user 38.49 sys
after: 301.57 real 262.69 user 37.11 sys
delta: -56.64 real -55.00 user -1.38 sys
#!/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:]
if cmd == 'help' and args:
cmd = args[0] # link to 'dates' for 'hg help dates'
node = nodes.reference(rawtext, '', linktext,
refuri="hg.1.html#%s" % cmd)
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)