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.
from __future__ import absolute_import, print_function
import os
from mercurial import (
dispatch,
)
def testdispatch(cmd):
"""Simple wrapper around dispatch.dispatch()
Prints command and result value, but does not handle quoting.
"""
print("running: %s" % (cmd,))
req = dispatch.request(cmd.split())
result = dispatch.dispatch(req)
print("result: %r" % (result,))
# create file 'foo', add and commit
f = open('foo', 'wb')
f.write('foo\n')
f.close()
testdispatch("add foo")
testdispatch("commit -m commit1 -d 2000-01-01 foo")
# append to file 'foo' and commit
f = open('foo', 'ab')
f.write('bar\n')
f.close()
# remove blackbox.log directory (proxy for readonly log file)
os.rmdir(".hg/blackbox.log")
# replace it with the real blackbox.log file
os.rename(".hg/blackbox.log-", ".hg/blackbox.log")
testdispatch("commit -m commit2 -d 2000-01-02 foo")
# check 88803a69b24 (fancyopts modified command table)
testdispatch("log -r 0")
testdispatch("log -r tip")