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.
#require execbit
$ umask 027
$ hg init test1
$ cd test1
$ touch a b
$ hg add a b
$ hg ci -m "added a b"
$ cd ..
$ hg clone test1 test3
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg init test2
$ cd test2
$ hg pull ../test1
pulling from ../test1
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
(run 'hg update' to get a working copy)
$ hg co
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ chmod +x a
$ hg ci -m "chmod +x a"
the changelog should mention file a:
$ hg tip --template '{files}\n'
a
$ cd ../test1
$ echo 123 >>a
$ hg ci -m "a updated"
$ hg pull ../test2
pulling from ../test2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg heads
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:c6ecefc45368
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a updated
$ hg history
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:c6ecefc45368
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a updated
changeset: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: added a b
$ hg -v merge
resolving manifests
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat a
123
$ [ -x a ]
$ cd ../test3
$ echo 123 >>b
$ hg ci -m "b updated"
$ hg pull ../test2
pulling from ../test2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg heads
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:dc57ead75f79
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: b updated
$ hg history
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:dc57ead75f79
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: b updated
changeset: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: added a b
$ hg -v merge
resolving manifests
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ ls -l ../test[123]/a > foo
$ cut -b 1-10 < foo
-rwxr-x---
-rwxr-x---
-rwxr-x---
$ hg debugindex a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 0 ..... 0 b80de5d13875 000000000000 000000000000 (re)
$ hg debugindex -R ../test2 a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 0 ..... 0 b80de5d13875 000000000000 000000000000 (re)
$ hg debugindex -R ../test1 a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 0 ..... 0 b80de5d13875 000000000000 000000000000 (re)
1 0 5 ..... 1 7fe919cc0336 b80de5d13875 000000000000 (re)
$ cd ..