Mercurial > hg
view tests/test-hardlinks.t @ 27475:a2e2a8fa5fd1
revlog: avoid string slice when decompressing u* chunks
Revlog chunks can be stored uncompressed. If the first byte of the
raw data is \0, we store the data as is. Else we prefix it with 'u'.
Before, we performed a string slice to strip out the 'u' prefix.
With this patch, we use a buffer to avoid an extra memory copy and
associated garbage collection overhead.
I was unable to verify any performance impact of this patch. For both
mozilla-central and the hg repos, the number of manifest revisions
with 'u' prefixes is very small - under 1%. So this change likely
isn't called enough to have an impact on manifest reading. However,
the reasoning behind this change is solid, so it should be safe.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 20 Dec 2015 16:00:27 -0800 |
parents | 4414d500604f |
children | b324b4e431e5 |
line wrap: on
line source
#require hardlink $ cat > nlinks.py <<EOF > import sys > from mercurial import util > for f in sorted(sys.stdin.readlines()): > f = f[:-1] > print util.nlinks(f), f > EOF $ nlinksdir() > { > find $1 -type f | python $TESTTMP/nlinks.py > } Some implementations of cp can't create hardlinks (replaces 'cp -al' on Linux): $ cat > linkcp.py <<EOF > from mercurial import util > import sys > util.copyfiles(sys.argv[1], sys.argv[2], hardlink=True) > EOF $ linkcp() > { > python $TESTTMP/linkcp.py $1 $2 > } Prepare repo r1: $ hg init r1 $ cd r1 $ echo c1 > f1 $ hg add f1 $ hg ci -m0 $ mkdir d1 $ cd d1 $ echo c2 > f2 $ hg add f2 $ hg ci -m1 $ cd ../.. $ nlinksdir r1/.hg/store 1 r1/.hg/store/00changelog.i 1 r1/.hg/store/00manifest.i 1 r1/.hg/store/data/d1/f2.i 1 r1/.hg/store/data/f1.i 1 r1/.hg/store/fncache 1 r1/.hg/store/phaseroots 1 r1/.hg/store/undo 1 r1/.hg/store/undo.backup.fncache 1 r1/.hg/store/undo.backupfiles 1 r1/.hg/store/undo.phaseroots Create hardlinked clone r2: $ hg clone -U --debug r1 r2 --config progress.debug=true linking: 1 linking: 2 linking: 3 linking: 4 linking: 5 linking: 6 linking: 7 linked 7 files Create non-hardlinked clone r3: $ hg clone --pull r1 r3 requesting all changes adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 2 files updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved Repos r1 and r2 should now contain hardlinked files: $ nlinksdir r1/.hg/store 2 r1/.hg/store/00changelog.i 2 r1/.hg/store/00manifest.i 2 r1/.hg/store/data/d1/f2.i 2 r1/.hg/store/data/f1.i 2 r1/.hg/store/fncache 1 r1/.hg/store/phaseroots 1 r1/.hg/store/undo 1 r1/.hg/store/undo.backup.fncache 1 r1/.hg/store/undo.backupfiles 1 r1/.hg/store/undo.phaseroots $ nlinksdir r2/.hg/store 2 r2/.hg/store/00changelog.i 2 r2/.hg/store/00manifest.i 2 r2/.hg/store/data/d1/f2.i 2 r2/.hg/store/data/f1.i 2 r2/.hg/store/fncache Repo r3 should not be hardlinked: $ nlinksdir r3/.hg/store 1 r3/.hg/store/00changelog.i 1 r3/.hg/store/00manifest.i 1 r3/.hg/store/data/d1/f2.i 1 r3/.hg/store/data/f1.i 1 r3/.hg/store/fncache 1 r3/.hg/store/phaseroots 1 r3/.hg/store/undo 1 r3/.hg/store/undo.backupfiles 1 r3/.hg/store/undo.phaseroots Create a non-inlined filelog in r3: $ cd r3/d1 >>> f = open('data1', 'wb') >>> for x in range(10000): ... f.write("%s\n" % str(x)) >>> f.close() $ for j in 0 1 2 3 4 5 6 7 8 9; do > cat data1 >> f2 > hg commit -m$j > done $ cd ../.. $ nlinksdir r3/.hg/store 1 r3/.hg/store/00changelog.i 1 r3/.hg/store/00manifest.i 1 r3/.hg/store/data/d1/f2.d 1 r3/.hg/store/data/d1/f2.i 1 r3/.hg/store/data/f1.i 1 r3/.hg/store/fncache 1 r3/.hg/store/phaseroots 1 r3/.hg/store/undo 1 r3/.hg/store/undo.backup.fncache 1 r3/.hg/store/undo.backup.phaseroots 1 r3/.hg/store/undo.backupfiles 1 r3/.hg/store/undo.phaseroots Push to repo r1 should break up most hardlinks in r2: $ hg -R r2 verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 2 files, 2 changesets, 2 total revisions $ cd r3 $ hg push pushing to $TESTTMP/r1 (glob) searching for changes adding changesets adding manifests adding file changes added 10 changesets with 10 changes to 1 files $ cd .. $ nlinksdir r2/.hg/store 1 r2/.hg/store/00changelog.i 1 r2/.hg/store/00manifest.i 1 r2/.hg/store/data/d1/f2.i 2 r2/.hg/store/data/f1.i 1 r2/.hg/store/fncache $ hg -R r2 verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 2 files, 2 changesets, 2 total revisions $ cd r1 $ hg up 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Committing a change to f1 in r1 must break up hardlink f1.i in r2: $ echo c1c1 >> f1 $ hg ci -m00 $ cd .. $ nlinksdir r2/.hg/store 1 r2/.hg/store/00changelog.i 1 r2/.hg/store/00manifest.i 1 r2/.hg/store/data/d1/f2.i 1 r2/.hg/store/data/f1.i 1 r2/.hg/store/fncache $ cd r3 $ hg tip --template '{rev}:{node|short}\n' 11:a6451b6bc41f $ echo bla > f1 $ hg ci -m1 $ cd .. Create hardlinked copy r4 of r3 (on Linux, we would call 'cp -al'): $ linkcp r3 r4 r4 has hardlinks in the working dir (not just inside .hg): $ nlinksdir r4 2 r4/.hg/00changelog.i 2 r4/.hg/branch 2 r4/.hg/cache/branch2-served 2 r4/.hg/cache/rbc-names-v1 2 r4/.hg/cache/rbc-revs-v1 2 r4/.hg/dirstate 2 r4/.hg/hgrc 2 r4/.hg/last-message.txt 2 r4/.hg/requires 2 r4/.hg/store/00changelog.i 2 r4/.hg/store/00manifest.i 2 r4/.hg/store/data/d1/f2.d 2 r4/.hg/store/data/d1/f2.i 2 r4/.hg/store/data/f1.i 2 r4/.hg/store/fncache 2 r4/.hg/store/phaseroots 2 r4/.hg/store/undo 2 r4/.hg/store/undo.backup.fncache 2 r4/.hg/store/undo.backup.phaseroots 2 r4/.hg/store/undo.backupfiles 2 r4/.hg/store/undo.phaseroots 2 r4/.hg/undo.backup.dirstate 2 r4/.hg/undo.bookmarks 2 r4/.hg/undo.branch 2 r4/.hg/undo.desc 2 r4/.hg/undo.dirstate 2 r4/d1/data1 2 r4/d1/f2 2 r4/f1 Update back to revision 11 in r4 should break hardlink of file f1: $ hg -R r4 up 11 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ nlinksdir r4 2 r4/.hg/00changelog.i 1 r4/.hg/branch 2 r4/.hg/cache/branch2-served 2 r4/.hg/cache/rbc-names-v1 2 r4/.hg/cache/rbc-revs-v1 1 r4/.hg/dirstate 2 r4/.hg/hgrc 2 r4/.hg/last-message.txt 2 r4/.hg/requires 2 r4/.hg/store/00changelog.i 2 r4/.hg/store/00manifest.i 2 r4/.hg/store/data/d1/f2.d 2 r4/.hg/store/data/d1/f2.i 2 r4/.hg/store/data/f1.i 2 r4/.hg/store/fncache 2 r4/.hg/store/phaseroots 2 r4/.hg/store/undo 2 r4/.hg/store/undo.backup.fncache 2 r4/.hg/store/undo.backup.phaseroots 2 r4/.hg/store/undo.backupfiles 2 r4/.hg/store/undo.phaseroots 2 r4/.hg/undo.backup.dirstate 2 r4/.hg/undo.bookmarks 2 r4/.hg/undo.branch 2 r4/.hg/undo.desc 2 r4/.hg/undo.dirstate 2 r4/d1/data1 2 r4/d1/f2 1 r4/f1 Test hardlinking outside hg: $ mkdir x $ echo foo > x/a $ linkcp x y $ echo bar >> y/a No diff if hardlink: $ diff x/a y/a Test mq hardlinking: $ echo "[extensions]" >> $HGRCPATH $ echo "mq=" >> $HGRCPATH $ hg init a $ cd a $ hg qimport -n foo - << EOF > # HG changeset patch > # Date 1 0 > diff -r 2588a8b53d66 a > --- /dev/null Thu Jan 01 00:00:00 1970 +0000 > +++ b/a Wed Jul 23 15:54:29 2008 +0200 > @@ -0,0 +1,1 @@ > +a > EOF adding foo to series file $ hg qpush applying foo now at: foo $ cd .. $ linkcp a b $ cd b $ hg qimport -n bar - << EOF > # HG changeset patch > # Date 2 0 > diff -r 2588a8b53d66 a > --- /dev/null Thu Jan 01 00:00:00 1970 +0000 > +++ b/b Wed Jul 23 15:54:29 2008 +0200 > @@ -0,0 +1,1 @@ > +b > EOF adding bar to series file $ hg qpush applying bar now at: bar $ cat .hg/patches/status 430ed4828a74fa4047bc816a25500f7472ab4bfe:foo 4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c:bar $ cat .hg/patches/series foo bar $ cat ../a/.hg/patches/status 430ed4828a74fa4047bc816a25500f7472ab4bfe:foo $ cat ../a/.hg/patches/series foo Test tags hardlinking: $ hg qdel -r qbase:qtip patch foo finalized without changeset message patch bar finalized without changeset message $ hg tag -l lfoo $ hg tag foo $ cd .. $ linkcp b c $ cd c $ hg tag -l -r 0 lbar $ hg tag -r 0 bar $ cat .hgtags 4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c foo 430ed4828a74fa4047bc816a25500f7472ab4bfe bar $ cat .hg/localtags 4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c lfoo 430ed4828a74fa4047bc816a25500f7472ab4bfe lbar $ cat ../b/.hgtags 4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c foo $ cat ../b/.hg/localtags 4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c lfoo $ cd ..