[PATCH 3 of 3 V3] manifest: increase lrucache from 3 to 4

Durham Goode durham at fb.com
Sat Nov 16 14:29:46 CST 2013


# HG changeset patch
# User Durham Goode <durham at fb.com>
# Date 1384216512 28800
#      Mon Nov 11 16:35:12 2013 -0800
# Node ID aadc27ceb73ca151a8168e58634bf735c1ac3c64
# Parent  91e01e4b76015511c29b4dbbcc2a73eeba2440b2
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 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):


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