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
"""
Tests the behavior of filelog w.r.t. data starting with '\1\n'
"""
from __future__ import absolute_import, print_function
from mercurial.node import (
hex,
nullid,
)
from mercurial import (
hg,
ui as uimod,
)
myui = uimod.ui()
repo = hg.repository(myui, path='.', create=True)
fl = repo.file('foobar')
def addrev(text, renamed=False):
if renamed:
# data doesn't matter. Just make sure filelog.renamed() returns True
meta = {'copyrev': hex(nullid), 'copy': 'bar'}
else:
meta = {}
lock = t = None
try:
lock = repo.lock()
t = repo.transaction('commit')
node = fl.add(text, meta, t, 0, nullid, nullid)
return node
finally:
if t:
t.close()
if lock:
lock.release()
def error(text):
print('ERROR: ' + text)
textwith = '\1\nfoo'
without = 'foo'
node = addrev(textwith)
if not textwith == fl.read(node):
error('filelog.read for data starting with \\1\\n')
if fl.cmp(node, textwith) or not fl.cmp(node, without):
error('filelog.cmp for data starting with \\1\\n')
if fl.size(0) != len(textwith):
error('FIXME: This is a known failure of filelog.size for data starting '
'with \\1\\n')
node = addrev(textwith, renamed=True)
if not textwith == fl.read(node):
error('filelog.read for a renaming + data starting with \\1\\n')
if fl.cmp(node, textwith) or not fl.cmp(node, without):
error('filelog.cmp for a renaming + data starting with \\1\\n')
if fl.size(1) != len(textwith):
error('filelog.size for a renaming + data starting with \\1\\n')
print('OK.')