# HG changeset patch
# User Durham Goode <durham@fb.com>
# Date 2013-11-12 00:35:12
# Node ID f8737bce736a6e8171ec955734aa6a19b8def074
# Parent  5fc2ae1c631b94ea83b2fe078c8acfea5aa55fbf

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.

diff --git a/mercurial/manifest.py b/mercurial/manifest.py
--- a/mercurial/manifest.py
+++ b/mercurial/manifest.py
@@ -30,8 +30,9 @@ class manifestdict(dict):
 
 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):