bdiff: don't check border condition in loop
This is pretty much a copy of d500ddae7494, just to a different loop.
The condition `p == plast` (`plast == a + len - 1`) was only true on
the final iteration of the loop. So it was wasteful to check for it
on every iteration. We decrease the iteration count by 1 and add an
explicit check for `p == plast` after the loop.
Again, we see modest wins.
From the mozilla-unified repository:
$ perfbdiff -m 3041e4d59df2
! wall 0.035502 comb 0.040000 user 0.040000 sys 0.000000 (best of 100)
! wall 0.030480 comb 0.030000 user 0.030000 sys 0.000000 (best of 100)
$ perfbdiff 0e9928989e9c --alldata --count 100
! wall 4.097394 comb 4.100000 user 4.100000 sys 0.000000 (best of 3)
! wall 3.597798 comb 3.600000 user 3.600000 sys 0.000000 (best of 3)
The 2nd example throws a total of ~3.3GB of data at bdiff. This
change increases the throughput from ~811 MB/s to ~924 MB/s.
#!/usr/bin/env python
#
# check-perf-code - (historical) portability checker for contrib/perf.py
from __future__ import absolute_import
import os
import sys
# write static check patterns here
perfpypats = [
[
(r'(branchmap|repoview)\.subsettable',
"use getbranchmapsubsettable() for early Mercurial"),
(r'\.(vfs|svfs|opener|sopener)',
"use getvfs()/getsvfs() for early Mercurial"),
(r'ui\.configint',
"use getint() instead of ui.configint() for early Mercurial"),
],
# warnings
[
]
]
def modulewhitelist(names):
replacement = [('.py', ''), ('.c', ''), # trim suffix
('mercurial%s' % (os.sep), ''), # trim "mercurial/" path
]
ignored = set(['__init__'])
modules = {}
# convert from file name to module name, and count # of appearances
for name in names:
name = name.strip()
for old, new in replacement:
name = name.replace(old, new)
if name not in ignored:
modules[name] = modules.get(name, 0) + 1
# list up module names, which appear multiple times
whitelist = []
for name, count in modules.items():
if count > 1:
whitelist.append(name)
return whitelist
if __name__ == "__main__":
# in this case, it is assumed that result of "hg files" at
# multiple revisions is given via stdin
whitelist = modulewhitelist(sys.stdin)
assert whitelist, "module whitelist is empty"
# build up module whitelist check from file names given at runtime
perfpypats[0].append(
# this matching pattern assumes importing modules from
# "mercurial" package in the current style below, for simplicity
#
# from mercurial import (
# foo,
# bar,
# baz
# )
((r'from mercurial import [(][a-z0-9, \n#]*\n(?! *%s,|^[ #]*\n|[)])'
% ',| *'.join(whitelist)),
"import newer module separately in try clause for early Mercurial"
))
# import contrib/check-code.py as checkcode
assert 'RUNTESTDIR' in os.environ, "use check-perf-code.py in *.t script"
contribpath = os.path.join(os.environ['RUNTESTDIR'], '..', 'contrib')
sys.path.insert(0, contribpath)
checkcode = __import__('check-code')
# register perf.py specific entry with "checks" in check-code.py
checkcode.checks.append(('perf.py', r'contrib/perf.py$', '',
checkcode.pyfilters, perfpypats))
sys.exit(checkcode.main())