Patchwork [5,of,5,V2] manifest: increase lrucache from 3 to 4

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Submitter Durham Goode
Date Nov. 13, 2013, 9:31 p.m.
Message ID <2aacf27a68fd58e96756.1384378266@dev350.prn1.facebook.com>
Download mbox | patch
Permalink /patch/2940/
State Superseded
Commit f8737bce736a6e8171ec955734aa6a19b8def074
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Durham Goode - Nov. 13, 2013, 9:31 p.m.
# HG changeset patch
# User Durham Goode <durham@fb.com>
# Date 1384216512 28800
#      Mon Nov 11 16:35:12 2013 -0800
# Node ID 2aacf27a68fd58e9675647612711a18b36023add
# Parent  21a4fec31a1f3bea839058b8fd7d7a85c096542c
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 5.3 seconds to 4.8 seconds.

Patch

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):