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.

# perf.py - asv benchmarks using contrib/perf.py extension
#
# Copyright 2016 Logilab SA <contact@logilab.fr>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from . import perfbench

@perfbench()
def track_tags(perf):
    return perf("perftags")

@perfbench()
def track_status(perf):
    return perf("perfstatus", unknown=False)

@perfbench(params=[('rev', ['1000', '10000', 'tip'])])
def track_manifest(perf, rev):
    return perf("perfmanifest", rev)

@perfbench()
def track_heads(perf):
    return perf("perfheads")