Re: memtest86 on the opteron

From: Eric W. Biederman (
Date: Mon Jun 09 2003 - 11:04:16 EST

Warren Togami <> writes:

> On Sat, 2003-06-07 at 20:27, Andi Kleen wrote:
> > Bryan O'Sullivan <> writes:
> >
> > > On Sat, 2003-06-07 at 14:43, Pavel Machek wrote:
> > >
> > > > Well, as opteron is i386-compatible, you should be able to simply use
> > > > i386 memtest...
> > >
> > > It doesn't work. Crashes and reboots the system shortly after it
> > > starts. The serial console support appears to have bit-rotted, too, so
> > > I've not been able to capture an output screen to diagnose the problem.
> >
> > The problem is the CPUID handling in memtest86. It does not expect
> > the 15 model number on AMD systems. Someone did a patch for it, but
> > I don't remember where they put it. Anyways should be easy to fix again
> > given the source.
> >
> If you find the patch I am interested in it. Please CC me.
> I am guessing that a normal 32bit compiled memtest86 wont be able to
> test beyond 4GB of RAM on AMD64?

memtest86 has PAE support so it should be able to test everything.
I have tested with 6GB of RAM on an old PIII.

Beyond the cpuid thing. There is a bug in the probing of how much memory
is cached. Last time I was playing with it I just disabled that section
of code.

If nothing else ping me a few times because I will need this shortly.
If it really does not work. And I am familiar with the code so I will
certainly get it fixed.

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This archive was generated by hypermail 2b29 : Sun Jun 15 2003 - 22:00:21 EST