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.

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# Dummy extension that adds a delay after acquiring a lock.

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#

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# This extension can be used to test race conditions between lock acquisition.

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from __future__ import absolute_import

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import os

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import time

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def reposetup(ui, repo):

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    class delayedlockrepo(repo.__class__):

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        def lock(self):

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            delay = float(os.environ.get('HGPRELOCKDELAY', '0.0'))

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            if delay:

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                time.sleep(delay)

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            res = super(delayedlockrepo, self).lock()

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            delay = float(os.environ.get('HGPOSTLOCKDELAY', '0.0'))

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            if delay:

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                time.sleep(delay)

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            return res

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    repo.__class__ = delayedlockrepo