MTRR survey: better X performance on systems with 3G or more RAM

[Bob Marcan]

On Sun, 12 Apr 2009 23:58:38 -0400 (EDT)
"D. Hugh Redelmeier" <hugh at mimosa.com> wrote:

> ==============================
> 
> What I'd like to know about your system:
> 
> Computer brand and model (or motherboard info): 
Supermicro  C2SBA motherboard, Intel(R) Core(TM)2 Quad CPU    Q9400  @ 2.66GHz
> video controller: 
Intel  82G33/G31 Express Integrated Graphics Controller
> X video driver:
X.Org X Server 1.5.3, open source "intel" driver
> RAM: 
8GB
> distro: 
Fedora 10 x86_64
> MTRR problem:
 $ /home/bob/tmp/01/mtrr-uncover/mtrr-uncover Initial MTRR
configuration: 1  0x000000000-0x1ffffffff write-back
         3  0x0bf600000-0x0bf7fffff uncachable
         4  0x0bf800000-0x0bfffffff uncachable
         0  0x0c0000000-0x0ffffffff uncachable
 2  0x200000000-0x23fffffff write-back

Final MTRR configuration:
 1' 0x000000000-0x07fffffff write-back
51' 0x080000000-0x0bfffffff write-back
         3  0x0bf600000-0x0bf7fffff uncachable
         4  0x0bf800000-0x0bfffffff uncachable
50  0x100000000-0x1ffffffff write-back
 2  0x200000000-0x23fffffff write-back

Commands for /proc/mtrr to make these changes:
disable=0
disable=1
base=0x000000000 size=0x080000000 type=write-back
base=0x080000000 size=0x040000000 type=write-back
base=0x100000000 size=0x100000000 type=write-back

> Fix: 
mtrr-uncover works, didn't try enable_mtrr_cleanup
> glxgears performance change: 
> 
Before:
12897 frames in 5.0 seconds = 2579.254 FPS
12993 frames in 5.0 seconds = 2598.539 FPS
12879 frames in 5.0 seconds = 2575.759 FPS
12998 frames in 5.0 seconds = 2599.503 FPS
12947 frames in 5.0 seconds = 2588.019 FPS
12713 frames in 5.0 seconds = 2542.563 FPS
13014 frames in 5.0 seconds = 2602.721 FPS
13012 frames in 5.0 seconds = 2602.385 FPS
13010 frames in 5.0 seconds = 2601.951 FPS
12875 frames in 5.0 seconds = 2574.983 FPS
12389 frames in 5.0 seconds = 2477.740 FPS
Now:
13053 frames in 5.0 seconds = 2610.419 FPS
13054 frames in 5.0 seconds = 2610.695 FPS
13048 frames in 5.0 seconds = 2609.514 FPS
13055 frames in 5.0 seconds = 2610.974 FPS
13053 frames in 5.0 seconds = 2610.452 FPS
13053 frames in 5.0 seconds = 2610.499 FPS
13056 frames in 5.0 seconds = 2611.072 FPS
13055 frames in 5.0 seconds = 2610.906 FPS
13054 frames in 5.0 seconds = 2610.624 FPS
13054 frames in 5.0 seconds = 2610.766 FPS
13055 frames in 5.0 seconds = 2610.859 FPS
13056 frames in 5.0 seconds = 2611.037 FPS
13054 frames in 5.0 seconds = 2610.709 FPS
13050 frames in 5.0 seconds = 2609.839 FPS

Best regards, Bob