On 04/26/2012 04:39 AM, Julian Stecklina wrote:
> Hello,
>
> looking at the ixgbe source in Linux 3.3.3 it seems that MSI-X is never
> enabled on uniprocessors.
>
> In ixgbe_set_interrupt_capability, it calculates the v_budget (vector
> budget) as  min(...,(int)num_online_cpus()) + NON_Q_VECTORS), which
> results in 2 (1 online CPU + NON_Q_VECTORS (1)).
>
> Later in ixgbe_acquire_msix_vectors we check if the vector budget is at
> least MIN_MSIX_COUNT (3), fail and fallback to MSI mode. The question is
> whether this is intended.
>
> I noticed this, because interrupt throttling seems to have no effect in
> MSI mode or at least I am unable to limit interrupt rate using the
> relevant module flags or ethtool. Can anyone comment on this?
>
> Regards, Julian
The MSI-X fallback is not intended.  To correct it you can just modify
MIN_MSIX_Q_VECTORS and set it to 1 instead of 2.

I'll look into the interrupt throttling issue on MSI interrupts and get
back to you.  As far as I know this is supposed to be working.

Thanks,

Alex

------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
E1000-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/e1000-devel
To learn more about Intel® Ethernet, visit 
http://communities.intel.com/community/wired

Reply via email to