merge: apply non-interactive working dir updates in parallel
This has a big effect on the performance of working dir updates.
Here are the results of update from null to the given rev in several
repos, on a Linux 3.2 system with 32 cores running ext4, with the progress
extension enabled.
repo rev plain parallel speedup
hg 7068089c95a2 0.9 0.3 3
mozilla-central fe1600b22c77 42.8 7.7 5.5
linux-2.6 9ef4b770e069 31.4 4.9 6.4
http://mercurial.selenic.com/bts/issue2137
Setup:
create a little extension that has 3 side-effects:
1) ensure changelog data is not inlined
2) make revlog to use lazyparser
3) test that repo.lookup() works
1 and 2 are preconditions for the bug; 3 is the bug.
$ cat > commitwrapper.py <<EOF
> from mercurial import extensions, node, revlog
>
> def reposetup(ui, repo):
> class wraprepo(repo.__class__):
> def commit(self, *args, **kwargs):
> result = super(wraprepo, self).commit(*args, **kwargs)
> tip1 = node.short(repo.changelog.tip())
> tip2 = node.short(repo.lookup(tip1))
> assert tip1 == tip2
> ui.write('new tip: %s\n' % tip1)
> return result
> repo.__class__ = wraprepo
>
> def extsetup(ui):
> revlog._maxinline = 8 # split out 00changelog.d early
> revlog._prereadsize = 8 # use revlog.lazyparser
> EOF
$ cat >> $HGRCPATH <<EOF
> [extensions]
> commitwrapper = `pwd`/commitwrapper.py
> EOF
$ hg init repo1
$ cd repo1
$ echo a > a
$ hg commit -A -m'add a with a long commit message to make the changelog a bit bigger'
adding a
new tip: 553596fad57b
Test that new changesets are visible to repo.lookup():
$ echo a >> a
$ hg commit -m'one more commit to demonstrate the bug'
new tip: 799ae3599e0e
$ hg tip
changeset: 1:799ae3599e0e
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: one more commit to demonstrate the bug
$ cd ..