[Beowulf] Problems with Dell M620 and CPU power throttling

Joe Landman landman at scalableinformatics.com
Sun Sep 1 21:02:10 PDT 2013


On 09/01/2013 11:49 PM, Christopher Samuel wrote:

> We pass through:
>
> intel_idle.max_cstate=0 processor.max_cstate=1
>
> on our SandyBridge nodes for just that reason.

Yes.  Mandatory on Sandy Bridge.  We often include cpu.idle=0 to handle 
an occasionally observed idle bug.

This is reminiscent of the "pausing" bug in Nehalem.  C state power 
transition, and suddenly the IOH/CPU loses seconds worth of clock ticks. 
  Very annoying.

> If you don't then the kernel will say "Oh, this is an Intel CPU, I
> know this!" (to paraphrase Jurassic Park) and enable every power
> saving feature it can find, regardless of what your BIOS/UEFI is set to.

:)

Power savings is great, when it works.  When it doesn't work, the 
wreckage thats left is epic.

-- 
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics, Inc.
email: landman at scalableinformatics.com
web  : http://scalableinformatics.com
        http://scalableinformatics.com/siflash
phone: +1 734 786 8423 x121
fax  : +1 866 888 3112
cell : +1 734 612 4615


More information about the Beowulf mailing list