[Beowulf] C-States and Latency

[Christopher Samuel]

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On 21/02/14 09:23, Kevin Van Workum wrote:

> Does anyone have a real-world application where setting
> intel_idle.max_cstate=0 and processor.max_cstate=0 actually makes a
> difference wrt application or network latency?

Mellanox's recommendation is:

intel_idle.max_cstate=0 processor.max_cstate=1

That's from:

http://www.mellanox.com/related-docs/prod_software/Performance_Tuning_Guide_for_Mellanox_Network_Adapters.pdf

We certainly saw performance problems with RHEL6 on Sandybridge systems
without that.

All the best!
Chris
- -- 
 Christopher Samuel        Senior Systems Administrator
 VLSCI - Victorian Life Sciences Computation Initiative
 Email: samuel at unimelb.edu.au Phone: +61 (0)3 903 55545
 http://www.vlsci.org.au/      http://twitter.com/vlsci

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