Re: solution Re: lost memory on a 4GB amd64
From: Sergei Haller
Date: Wed Oct 27 2004 - 10:49:56 EST
On Wed, 27 Oct 2004, Andreas Klein (AK) wrote:
AK> Hello,
AK>
AK> the problem has been verified by Tyan. It is definately a hardware issue.
AK> The Tyan and AMD engineers are developing a solution (BIOS) for the
AK> problem.
AK> They will fix the problem for the S2885, as weel as for the S2875 boards.
Are you sure this is the same problem, that I have? You discovered
Problems with memtest86:
> Memtest sees 0-2GB mem usable and 4-6GB unusable (complains
> about each memory address).
I didn't:
> memtest86 is happy with the memory.
The next difference:
You have the S2885 (thunder K8W) and S2875S (tiger K8W single processor)
boards and I have a S2875 (tiger K8W double processor)
I summarize (again) my problems:
Independantly of the memory settings in the BIOS:
- non-SMP Kernel is stable
- memtest86 does not report any errors
If the memory (4GB) is set up in one block (0-4GB) in the BIOS, then
- SMP Kernel is stable
If the memory (4GB) is set up in two blocks (eg. 0-3GB, 4-5GB) in the
BIOS, then
- SMP Kernel is stable _if_and_only_if_ NUMA is _disabled_.
BTW.: I won't be able to flash a new BIOS to our machine, since it is in
production use and runs _rock_stable_ with _full_memory_ after we
_disabled_ NUMA support in the kernel. (see the two small programs posted
by me and by Andi Kleen)
What I COULD do is running some tests if needed. (e.g. to check if the
Board/BIOS is lying about its capabilities)
Sergei
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