memtest question on 8 GB RAM AMD64 system

[Josh Carroll]

On Thu, Apr 9, 2009 at 2:43 PM, Dino Vliet <dino_vliet at yahoo.com> wrote:
> Dear freebsd people,
>
> I have just installed 4 x 2gb kingston memory banks (Kingston HyperX 4GB 800mhz DDR2 Non-ECC CL5 (5-5-5-15) DIMM) onto my AMD 64 system with a X2 5200 CPU. The motherboard I have in this system is MSI K9AG Neo2-Digital.
>
> The system boots fine and I wanted to try memtest to see if there would be errors. So I installed that /usr/ports/sysutils/memtest port and did
>
> # memtest 2400
>
> The output I got is:
> Continuing with unlocked memory; testing will be slower and less reliable.
>
> .......
> pagesize 4096
> pagesizemask is 0xfffffffffffff000
> want 2400MB (2516582400 bytes)
> got   2400MB (2516582400 bytes), trying mlock .......failed for unknown reason
> Loop 1:
> .....
>
> In my /etc/rc/conf file I had added these lines in the past (when I had 4gb RAM installed in it)
>
> sysctl -w kern.ipc.shmmax=1954311424
> sysctl -w kern.ipc.shmall=238000
>
> What is the case here? Why is memtest failing to use mlock? How can I eventually make sure I can run memtest with 8000mb?
>
> The purpose of this machine is that it will be used for a various data intensive tasks where I need to be able to allocate as much memory possible. I am running a postgresql database server on it as well to store my source data.

I've run into similar problems trying to use that particular memtest port.

If you want to more reliably test the memory, I'd suggest using
memtest86+ from http://www.memtest.org/

It is much more thorough and runs independent of the operating system.

Regards,
Josh