Robert Hancock wrote:
Peter Rabbitson wrote:
H. Peter Anvin wrote:
What does /proc/mtrr look like in the two cases?
Identical for mem=3900 and without it.
reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1
reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
reg02: base=0xc0000000 (3072MB), size= 512MB: write-back, count=1
reg03: base=0xe0000000 (3584MB), size= 256MB: write-back, count=1
reg04: base=0xf0000000 (3840MB), size= 128MB: write-back, count=1
reg05: base=0xf8000000 (3968MB), size= 32MB: write-back, count=1
Looks like another case of bad MTRRs on an Intel motherboard? The BIOS
is marking only memory up to 4000MB as cacheable, but the actual memory
extends up to about 4031MB. Therefore anything that accesses the top
31MB of memory will run very slow.
Ah, it all makes sense now. In this case I assume mem=4000 is perfectly
safe and usable for the time being. In the beginning I tried with
mem=4g, which obviously did not work. If anyone is interested in adding
an exception/workaround for this particular motherboard, I'd be happy to
help with testing. I have added more information about the system:
current kernel config [1], output of `lspci -vv`[2], dmesg with mem=4000[3].
Thank you!
Peter
[1] http://rabbit.us/pool/4g/config-2.6.21.5.arzamas.6.txt
[2] http://rabbit.us/pool/4g/lspci_4000.txt
[3] http://rabbit.us/pool/4g/dmesg_4000.txt
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
