Re: [E1000-devel] RSS Configuration in ixgbe (Queue limit?)

[Skidmore, D. C <don...@in...>]

> -----Original Message-----
> From: Scott Silverman [mailto:ssi...@si...]
> Sent: Tuesday, December 24, 2013 6:28 AM
> To: e10...@li...
> Subject: [E1000-devel] RSS Configuration in ixgbe (Queue limit?)
> 
> In attempting to troubleshoot the issue with ring buffer drops I wrote about
> in another thread, I've noticed some behavior in ixgbe that does not match
> documentation.
> 
> Configuring RSS (with RSS=#,#) to a value between 1-16 works as expected.
> Setting no value (or setting 0, default) configures as many queues as there
> are cores (on a 20 core box with hyperthreading, that is 40 cores per
> interface). The documentation says that it will only configure the lesser of
> cores or 16.
> 
> Attempting to manually set a value higher than 16 fails, and acts as if a value
> of 0 was entered. (i.e. RSS=24,24 has no effect, and the full 40 queues are
> created).
> 
> Should it be stopping at 16? If not, why can't I manually choose queue counts
> of 17-(cores-1) queues?
> 
> 
> Thanks,
> 
> Scott Silverman

Hey Scott,

While the driver can only use RSS to filter to 16 queue it can support more queues in general.  And since ATR is on by default and can support your 40 queues so they are all allocated.  

Thanks,
-Don Skidmore <don...@in...>