update: 
    For glbenchmark Egypt, the frames value changed from 11384.0 to 8128.0,
about 28% regression. 
    For lightsmark, the fps value changed from 28.69 to 24.15. about 14% regression.

I have put some patches and bisected again,get the result as follow:

The first bad commit could be any of:
 1 d7b33309fe160212f2eb73f471f3aedcb5d0b5c1
 2 da2816a45e6e3a33246a341fee72e6f893f315d9
 3 005149d5860ad55c5e58e2de8a138e3a763f2036
 4 c2ddde70daece24d1eb7185946032158993a9e4d
 5 278e77a1192d5251c5b70a555e676f72b446e8e1
 6 c3c7cbd15418293208034e8970d626b5998abd4b
 

These commit couldn't be build successfully.

for bisecting, the one before these commits is bad commit :
commit: 24da7335b22432ef4c2d57cab86e4b8fbe8733d5
Author: Chad Versace <chad.versace@linux.intel.com>
Date:   Tue Nov 15 10:05:21 2011 -0800

and the next one of these commit is good commit: 
commit: 19faa12bb751eabc1590d042adbd345b89542de0
Author: Chad Versace <chad.versace@linux.intel.com>
Date:   Sun Nov 13 23:05:47 2011 -0800

By the way, I find 3DMMES/uimark has about 43.67 % regression , changed from  44.9563 to 25.3248  .

I'm surprised to discover that this merge caused a performance regression. I'm not denying that it did, just stating my surprise. I tested Egypt's performance on my HiZ branch *before* the merge, and there existed a performance *improvement*. Also, Phoronix performed several benchmarks after the merge, and discovered no performance degradations, only improvements.

I will try look into this on Monday. What git url should I use to clone 3dmmes?

you can download from:
http://tinderbox.sh.intel.com/games/glbenchmark.tar.gz
after extract it ,you can run it as follow steps:
1. cd /glbenchmark/projects/Linux/
2. rm -f GLBenchTestInput.txt
3. cp  Egypt.txt GLBenchTestInput.txt
4. start X and gnome-session
5. ./glbenchmark_nogui

(In reply to comment #3)
> I'm surprised to discover that this merge caused a performance regression. I'm
> not denying that it did, just stating my surprise. I tested Egypt's performance
> on my HiZ branch *before* the merge, and there existed a performance
> *improvement*. Also, Phoronix performed several benchmarks after the merge, and
> discovered no performance degradations, only improvements.
> 
> I will try look into this on Monday. What git url should I use to clone 3dmmes?

(In reply to comment #3)

You can also download 3DMMES from: http://tinderbox.sh.intel.com/games/3DMMES.tar.gz

> I'm surprised to discover that this merge caused a performance regression. I'm
> not denying that it did, just stating my surprise. I tested Egypt's performance
> on my HiZ branch *before* the merge, and there existed a performance
> *improvement*. Also, Phoronix performed several benchmarks after the merge, and
> discovered no performance degradations, only improvements.
> 
> I will try look into this on Monday. What git url should I use to clone 3dmmes?

http://lists.freedesktop.org/archives/mesa-dev/2011-December/016326.html

commit 7f854a5028ef00a0e041e78a770456204dc58eef
Author: Eric Anholt <eric@anholt.net>
Date:   Fri Dec 16 13:18:55 2011 -0800

    intel: Fix performance regression in Lightsmark since HiZ changes.
    
    Since the refactor in d7b33309fe160212f2eb73f471f3aedcb5d0b5c1, depth
    in the miptree changed from 1 to 6, so we always decided it didn't
    match, and we would relayout to something that would still not
    "match".
    
    Improves performance 23.8% (+/- 1.1%, n=4)
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=43329