Messages in this thread | | | From | Volker Armin Hemmann <> | Subject | about mtrr | Date | Tue, 26 May 2009 22:01:04 +0200 |
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Hello, this is an amd64 system. AMD X2 CPU, Am2+ motherboard with A770 chipset and SB 700 southbridge -A770Crossfire from Asrock. Latest bios
my /proc/mtrr always roughly looking like that: reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back reg02: base=0x0c0000000 ( 3072MB), size= 128MB, count=1: write-back reg03: base=0x0c8000000 ( 3200MB), size= 64MB, count=1: write-back reg04: base=0x0cc000000 ( 3264MB), size= 32MB, count=1: write-back reg05: base=0x0ce000000 ( 3296MB), size= 16MB, count=1: write-back
now it looks like that (with ati driver loaded, without, just the last line is missing):
cat /proc/mtrr reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back reg02: base=0x0c0000000 ( 3072MB), size= 128MB, count=1: write-back reg03: base=0x0c8000000 ( 3200MB), size= 64MB, count=1: write-back reg04: base=0x0cc000000 ( 3264MB), size= 32MB, count=1: write-back reg05: base=0x0ce000000 ( 3296MB), size= 16MB, count=1: write-back reg06: base=0x0d0000000 ( 3328MB), size= 256MB, count=1: write-combining
which was ok as long as I had 4gb of ram.
But I have a 6gb now - and with the additional 2gb performance took a hit.
I would like to know why roughly 2.5gb are not covered by mtrr's and is there a way to force the kernel to cover the whole range without doing it manually? I played with mtrr_spare_reg_nr= and MTRR cleanup support without any changes at all. 2.6.27, 2.6.28, 2.6.29 - all three versions show the same mtrr. Attached are dmesg and config.
Glück Auf, Volker [unhandled content-type:application/x-gzip][unhandled content-type:application/x-gzip] | |