Re: AVX "Sandy Bridge" hardware issue?

[Chris Friesen <chris.friesen@genband.com>]

On 07/12/2011 06:49 PM, Andi Kleen wrote:
> MK<mk@cognitivedissonance.ca>  writes:
>>
>> In which Andreas Schwab points out (rightly or wrongly) that according
>> to the /proc/cpuinfo from the slice, the processor actually does not
>> support AVX.  However,  the "model name", "Intel(R) Xeon(R) CPU
>> E31230", is according to this a Sandy Bridge processor with AVX:
>
> If it's in a VM then the VM may not expose AVX to the guest
> (the VMs have to do that explicitely because AVX has additional state).
> If it's not in /proc/cpuinfo on the guest that's likely the case.

The OP mentioned that he's using OpenVZ, so it's running in a container 
(chroot on steroids), not a "true" VM.

Each instance runs the same kernel, they're isolated from the other 
instances using filesystem/process/network namespaces.

That said, /proc/cpuinfo is virtualized somehow by the containerization 
since it shows only the cpus assigned to the container--it seems 
plausible that they screwed up the cpu flags while doing it.

I think your suggestion of talking to the vendor is the correct next step.

Chris


-- 
Chris Friesen
Software Developer
GENBAND
chris.friesen@genband.com
www.genband.com