revset: optimize missing ancestor expressions
A missing ancestor expression is any expression of the form (::x - ::y) or
equivalent. Such expressions are remarkably common, and so far have involved
multiple walks down the DAG, followed by a set difference operation.
With this patch, such expressions will be transformed into uses of the fast
algorithm at ancestor.missingancestor.
For a repository with over 600,000 revisions, perfrevset for '::tip - ::-10000'
returns:
Before: ! wall 3.999575 comb 4.000000 user 3.910000 sys 0.090000 (best of 3)
After: ! wall 0.132423 comb 0.130000 user 0.130000 sys 0.000000 (best of 75)
$ "$TESTDIR/hghave" inotify || exit 80
$ hg init
$ echo "[extensions]" >> $HGRCPATH
$ echo "inotify=" >> $HGRCPATH
inserve
$ hg inserve -d --pid-file=hg.pid
$ cat hg.pid >> "$DAEMON_PIDS"
let the daemon finish its stuff
$ sleep 1
empty
$ hg debuginotify
directories being watched:
/
.hg/
$ mkdir a
$ sleep 1
only 'a
$ hg debuginotify
directories being watched:
/
.hg/
a/
$ rmdir a
$ sleep 1
empty again
$ hg debuginotify
directories being watched:
/
.hg/
$ "$TESTDIR/killdaemons.py" hg.pid