manifest: increase lrucache from 3 to 4
During a commit amend there are 4 manifests being handled:
- original commit
- temporary commit
- amended commit
- merge base
This causes a manifest cache miss which hurts perf on large repos. On a large
repo, this fix causes amend to go from 6 seconds to 5.5 seconds.
--- a/mercurial/manifest.py Mon Nov 11 16:42:49 2013 -0800
+++ b/mercurial/manifest.py Mon Nov 11 16:35:12 2013 -0800
@@ -30,8 +30,9 @@
class manifest(revlog.revlog):
def __init__(self, opener):
- # we expect to deal with not more than three revs at a time in merge
- self._mancache = util.lrucachedict(3)
+ # we expect to deal with not more than four revs at a time,
+ # during a commit --amend
+ self._mancache = util.lrucachedict(4)
revlog.revlog.__init__(self, opener, "00manifest.i")
def parse(self, lines):