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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Create an empty repo:

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  $ hg init a

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  $ cd a

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Try some commands:

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  $ hg log

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  $ hg grep wah

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  [1]

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  $ hg manifest

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  $ hg verify

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  checking changesets

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  checking manifests

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  crosschecking files in changesets and manifests

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  checking files

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  0 files, 0 changesets, 0 total revisions

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Check the basic files created:

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  $ ls .hg

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  00changelog.i

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  requires

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  store

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Should be empty:

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  $ ls .hg/store

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Poke at a clone:

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  $ cd ..

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  $ hg clone a b

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  updating to branch default

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  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

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  $ cd b

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  $ hg verify

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  checking changesets

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  checking manifests

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  crosschecking files in changesets and manifests

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  checking files

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  0 files, 0 changesets, 0 total revisions

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  $ ls .hg

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  00changelog.i

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  hgrc

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  requires

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  store

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Should be empty:

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  $ ls .hg/store

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  $ cd ..