dirstate: when calling rebuild(), avoid some N^2 codepaths
I had a user repo with 200k files in it. Calling `hg debugrebuilddirstate` took
tens of minutes (I didn't wait for it). In that situation,
changedfiles==allfiles, and both are lists. This meant that we had to run an
average of 100k comparisons, for each of 200k files, just to check whether a
file needed to have normallookup called (it always did), or drop.
While it's probably not a huge issue, in my very awkward synthetic benchmark I
wrote (not using a benchmark library or anything), I was seeing some slowdowns
for small-changedfiles and very-large-allfiles invocations, with an inflection
somewhere around 10 items in changedfiles (regardless of the size of allfiles);
above 10 items in changedfiles, the new code appears to always be faster. For
the case of 50k files in changedfiles and the same items in allfiles, I'm seeing
differences of 15s of just running comparisons vs. 0.003793s. I haven't bothered
to run a comparison of 200k items in changedfiles and allfiles. :)
Differential Revision: https://phab.mercurial-scm.org/D7665
This test file aims at test topological iteration and the various configuration it can has.
$ cat >> $HGRCPATH << EOF
> [ui]
> logtemplate={rev}\n
> EOF
On this simple example, all topological branch are displayed in turn until we
can finally display 0. this implies skipping from 8 to 3 and coming back to 7
later.
$ hg init test01
$ cd test01
$ hg unbundle $TESTDIR/bundles/remote.hg
adding changesets
adding manifests
adding file changes
added 9 changesets with 7 changes to 4 files (+1 heads)
new changesets bfaf4b5cbf01:916f1afdef90 (9 drafts)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg log -G
o 8
|
| o 7
| |
| o 6
| |
| o 5
| |
| o 4
| |
o | 3
| |
o | 2
| |
o | 1
|/
o 0
(display all nodes)
$ hg log -G -r 'sort(all(), topo)'
o 8
|
o 3
|
o 2
|
o 1
|
| o 7
| |
| o 6
| |
| o 5
| |
| o 4
|/
o 0
(display nodes filtered by log options)
$ hg log -G -r 'sort(all(), topo)' -k '.3'
o 8
|
o 3
|
~
o 7
|
o 6
|
~
(revset skipping nodes)
$ hg log -G --rev 'sort(not (2+6), topo)'
o 8
|
o 3
:
o 1
|
| o 7
| :
| o 5
| |
| o 4
|/
o 0
(begin) from the other branch
$ hg log -G -r 'sort(all(), topo, topo.firstbranch=5)'
o 7
|
o 6
|
o 5
|
o 4
|
| o 8
| |
| o 3
| |
| o 2
| |
| o 1
|/
o 0
Topological sort can be turned on via config
$ cat >> $HGRCPATH << EOF
> [experimental]
> log.topo=true
> EOF
$ hg log -G
o 8
|
o 3
|
o 2
|
o 1
|
| o 7
| |
| o 6
| |
| o 5
| |
| o 4
|/
o 0
Does not affect non-graph log
$ hg log -T '{rev}\n'
8
7
6
5
4
3
2
1
0