# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 2012-04-27 18:07:29
# Node ID 95698ee291814abc4d23e614b4eedd8dfe07ee2d
# Parent  9eba72cdde3464784bcdfff30aebc7902553347c

revlog: backout e5750c6716eb

This regresses performance of 'hg branches', presumably because it's
visiting the revlog in the wrong order. This suggests we either need
to fix the branch code or add some read-behind to mitigate the effect.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -812,7 +812,7 @@ class revlog(object):
         else:
             df = self.opener(self.datafile)
 
-        readahead = max(_chunksize, length)
+        readahead = max(65536, length)
         df.seek(offset)
         d = df.read(readahead)
         df.close()