Memory Issues: /proc/kcore vs. free

[Gary Stiehr]

Hi,
	We used to have some nodes that had SuperMicro boards and others that
had a different brand motherboard.  Each node had 128MB of RAM.  The
SuperMicro-based nodes, however, only showed 64MB of RAM when running
free (even though the bios recognized all 128 MB).  Supposedly the bios
on these boards did not properly pass some information to the linux
kernel about the amount of memory.  It was suggested that we boot with

	linux mem=128MB

at the lilo prompt or add

	append="mem=128M"

to /etc/lilo.conf in the "image" sections.

Unfortunately, this did not work for us but we feel that there may have
been other complications keeping this suggestion from working for us. 
We did not have those nodes for much longer and our jobs were not very
memory intensive so we did not investigate it much further.  But I think
that the suggestion above was a good starting point and hopefully it
WILL help you.

-- 
Gary Stiehr
Information Technology Services
University of Missouri - St. Louis
gary at umsl.edu

"Christopher L. Rogers" wrote:
> 
> folks:
> 
> i am trying to determine whether or not i have
> some bad memory or not on some of my beowulf nodes.
> One thing i noticed right away is that ls -l of /proc/kcore
> maxs out at 940 MB for physical ram greater than 1 GB.
> 
> I'm running 2048 MB, which the bios detects. free reports
> 2074 MB but as i said earlier /proc/kcore reports 940 MB.
> (i do have mem=2048M appended in my lilo.conf)
> 
> So is this cause for alarm? Which is the true amount the
> system sees? I need to routinely run jobs on these nodes
> that are about 1 to 1.25 GB., so it makes a difference.
> 
> The system in question is a dual PIII Supermicro 370DL3
> with their latest bios. The bios reports the 2 GB of ram
> as PC133, and the vendor claims it's true registered ECC.
> The kernel is a stock Redhat 7.0 "enterprise" kernel
> (2.2.16-22enterprise)
> 
> Thanks for all your help.
> 
> -Chris Rogers
> crogers at sas.upenn.edu
> 
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