On Thu, 25 Jan 2007 21:22:11 +0100
Svata Dedic <[EMAIL PROTECTED]> wrote:

> Hello,
> 
> I am having troubles to set up network interfaces on our machine to
> properly use SMP Linux features. There are two Broadcom Nextreme II
> ethernet NICs onboard a 2x dual-core CPU machine.
> 
> My kernel has SMP and Message-Signaled Interrupts (MSI) enabled. When I
> boot with MSI enabled, I can see in /proc/interrupts that each of the
> NICs got a unique interrupt assigned. But all traffic generated to the
> 1st NIC goes to the CPU#0, other CPUs show 0 processed interrupts in the
> /proc/interrupts.

This is actually a designed beneficial state. If IRQ's happen on different
CPU's then there is more cache memory thrashing and performance is lower.

> I tried to assign the interrupt to a specific CPU (single bit in
> smp_affinity, tried each of the 4 CPU cores), with the same results;
> althought smp_affinity said e.g. 4, everything was processed by CPU#0
> 
> When the machine booted with "pci=nomsi" kernel parameter, the NICs were
> assigned a shared IO-APIC interrupt, but the intr processing was
> properly distributed among CPU cores as requested by the affinity_mask.
> 
> What am I doing wrong ?
> 
> Thanks for any advice,
> -Svata
> -
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-- 
Stephen Hemminger <[EMAIL PROTECTED]>
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