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
#
# simple script to be used in hooks
#
# put something like this in the repo .hg/hgrc:
#
# [hooks]
# changegroup = python "$TESTDIR/printenv.py" <hookname> [exit] [output]
#
# - <hookname> is a mandatory argument (e.g. "changegroup")
# - [exit] is the exit code of the hook (default: 0)
# - [output] is the name of the output file (default: use sys.stdout)
# the file will be opened in append mode.
#
from __future__ import absolute_import
import os
import sys
try:
import msvcrt
msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
pass
exitcode = 0
out = sys.stdout
name = sys.argv[1]
if len(sys.argv) > 2:
exitcode = int(sys.argv[2])
if len(sys.argv) > 3:
out = open(sys.argv[3], "ab")
# variables with empty values may not exist on all platforms, filter
# them now for portability sake.
env = [(k, v) for k, v in os.environ.iteritems()
if k.startswith("HG_") and v]
env.sort()
out.write("%s hook: " % name)
if os.name == 'nt':
filter = lambda x: x.replace('\\', '/')
else:
filter = lambda x: x
vars = ["%s=%s" % (k, filter(v)) for k, v in env]
out.write(" ".join(vars))
out.write("\n")
out.close()
sys.exit(exitcode)