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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# The test-repo is a live hg repository which may have evolution

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# markers created, e.g. when a ~/.hgrc enabled evolution.

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#

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# Tests are run using a custom HGRCPATH, which do not

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# enable evolution markers by default.

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#

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# If test-repo includes evolution markers, and we do not

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# enable evolution markers, hg will occasionally complain

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# when it notices them, which disrupts tests resulting in

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# sporadic failures.

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#

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# Since we aren't performing any write operations on the

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# test-repo, there's no harm in telling hg that we support

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# evolution markers, which is what the following lines

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# for the hgrc file do:

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cat >> $HGRCPATH << EOF

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[experimental]

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evolution=createmarkers

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EOF