Thank you for your advice, Zack, but this kernel doesn't solve the performance problem as well. (It does, however, change the MTRR allocation as intended.)
Repository kernel:
$ uname -a
Linux corner 2.6.28-12-generic #43-Ubuntu SMP Fri May 1 19:27:06 UTC 2009 i686 GNU/Linux
$ cat /proc/mtrr
reg00: base=0x000000000 ( 0MB), size= 1024MB, count=1: write-back
reg01: base=0x03f800000 ( 1016MB), size= 8MB, count=1: uncachable
Kernel from bug 314928:
$ uname -a
Linux corner 2.6.28-13-generic #44~lp314928apw1 SMP Wed May 6 08:32:32 UTC 2009 i686 GNU/Linux
$ cat /proc/mtrr
reg00: base=0x000000000 ( 0MB), size= 1024MB, count=1: write-back
reg01: base=0x03f800000 ( 1016MB), size= 8MB, count=1: uncachable
reg02: base=0x0e0000000 ( 3584MB), size= 256MB, count=1: write-combining
Thank you for your advice, Zack, but this kernel doesn't solve the performance problem as well. (It does, however, change the MTRR allocation as intended.)
Repository kernel:
$ uname -a
Linux corner 2.6.28-12-generic #43-Ubuntu SMP Fri May 1 19:27:06 UTC 2009 i686 GNU/Linux
$ cat /proc/mtrr
reg00: base=0x000000000 ( 0MB), size= 1024MB, count=1: write-back
reg01: base=0x03f800000 ( 1016MB), size= 8MB, count=1: uncachable
Kernel from bug 314928:
$ uname -a
Linux corner 2.6.28-13-generic #44~lp314928apw1 SMP Wed May 6 08:32:32 UTC 2009 i686 GNU/Linux
$ cat /proc/mtrr
reg00: base=0x000000000 ( 0MB), size= 1024MB, count=1: write-back
reg01: base=0x03f800000 ( 1016MB), size= 8MB, count=1: uncachable
reg02: base=0x0e0000000 ( 3584MB), size= 256MB, count=1: write-combining