perf: add threading capability to perfbdiff
Since we are releasing the GIL during diffing, it is interesting to see how a
thread pool would perform on diffing. We add a new `--threads` argument to
commands. Synchronizing the thread pool is a bit complex because we want to be
able to reuse it from one run to another.
On my computer (i7 with 4 cores + hyperthreading), I get the following data for
about 12000 revisions:
threads wall comb wall gain comb overhead
none 31.596715 31.59 0.00% 0.00%
1 31.621228 31.62 -0.08% 0.09%
2 16.406202 32.8 48.08% 3.83%
3 11.598334 34.76 63.29% 10.03%
4 9.205421 36.77 70.87% 16.40%
5 8.517604 42.51 73.04% 34.57%
6 7.94645 47.58 74.85% 50.62%
7 7.434972 51.92 76.47% 64.36%
8 7.070638 55.34 77.62% 75.18%
Compared to the feature disabled (threads=0), the overhead is negligible with
the threading code (threads=1), and the gain is already 48% with two threads.
#require svn svn-bindings
$ filter_svn_output () {
> egrep -v 'Committing|Updating|(^$)' | sed -e 's/done$//' || true
> }
$ cat <<EOF >> $HGRCPATH
> [extensions]
> convert =
> mq =
> EOF
$ SVNREPOPATH=`pwd`/svn-repo
#if windows
$ SVNREPOURL=file:///`$PYTHON -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#else
$ SVNREPOURL=file://`$PYTHON -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#endif
$ svnadmin create "$SVNREPOPATH"
$ cat > "$SVNREPOPATH"/hooks/pre-revprop-change <<EOF
> #!/bin/sh
>
> REPOS="$1"
> REV="$2"
> USER="$3"
> PROPNAME="$4"
> ACTION="$5"
>
> if [ "$ACTION" = "M" -a "$PROPNAME" = "svn:log" ]; then exit 0; fi
> if [ "$ACTION" = "A" -a "$PROPNAME" = "hg:convert-branch" ]; then exit 0; fi
> if [ "$ACTION" = "A" -a "$PROPNAME" = "hg:convert-rev" ]; then exit 0; fi
>
> echo "Changing prohibited revision property" >&2
> exit 1
> EOF
$ chmod +x "$SVNREPOPATH"/hooks/pre-revprop-change
$ svn co "$SVNREPOURL" "$SVNREPOPATH"-wc
Checked out revision 0.
$ cd "$SVNREPOPATH"-wc
$ echo a > a
$ svn add a
A a
$ svn ci -m'added a' a | filter_svn_output
Adding a
Transmitting file data .
Committed revision 1.
$ cd ..
initial roundtrip
$ hg convert -s svn -d hg "$SVNREPOPATH"-wc "$SVNREPOPATH"-hg | grep -v initializing
scanning source...
sorting...
converting...
0 added a
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
second roundtrip should do nothing
$ hg convert -s svn -d hg "$SVNREPOPATH"-wc "$SVNREPOPATH"-hg
scanning source...
sorting...
converting...
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
new hg rev
$ hg clone "$SVNREPOPATH"-hg "$SVNREPOPATH"-work
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd "$SVNREPOPATH"-work
$ echo b > b
$ hg add b
$ hg ci -mb
adding an empty revision
$ hg qnew -m emtpy empty
$ hg qfinish -a
$ cd ..
echo hg to svn
$ hg --cwd "$SVNREPOPATH"-hg pull -q "$SVNREPOPATH"-work
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
1 b
0 emtpy
svn back to hg should do nothing
$ hg convert -s svn -d hg "$SVNREPOPATH"-wc "$SVNREPOPATH"-hg
scanning source...
sorting...
converting...
hg back to svn should do nothing
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
verify which shamap format we are storing and must be able to handle
$ cat svn-repo-hg/.hg/shamap
svn:????????-????-????-????-????????????@1 ???????????????????????????????????????? (glob)
svn:????????-????-????-????-????????????@2 ???????????????????????????????????????? (glob)
svn:????????-????-????-????-????????????@2 ???????????????????????????????????????? (glob)
$ cat svn-repo-wc/.svn/hg-shamap
???????????????????????????????????????? 1 (glob)
???????????????????????????????????????? svn:????????-????-????-????-????????????@2 (glob)
???????????????????????????????????????? svn:????????-????-????-????-????????????@2 (glob)