[Lustre-discuss] socknal_sd00 100% lower?

[Isaac Huang]

On Fri, Mar 07, 2008 at 12:53:52AM -0500, Brock Palen wrote:
> If our IO servers are seeing extended periods of socknal_sd00 at 100%  
> cpu,  Would this cause a bottle neck?  If so its a single homed  
> hosts, would adding another interface to the host help?

To quote the Lustre Manual:

enable_irq_affinity (1,Wc) is a boolean that determines whether to
enable IRQ affinity. When set, socklnd attempts to maximize
performance by handling device interrupts and data movement for
particular (hardware) interfaces on particular CPUs. This option is
not available on all platforms. This option requires an SMP system to
exist and produces best performance with multiple NICs. Systems with
multiple CPUs and a single NIC may see increase in the performance
with this parameter disabled.

So if you have multiple CPUs and a single NIC (or more precisely Lustre 
only uses a single NIC) I'd suggest to try:
options ksocklnd enable_irq_affinity=0

Isaac