[ofa-general] which CPU will ib_mthca interrupt next?

[Roland Dreier]

 > I've no idea which CPU ib_mthca will interrupt next.  ISTR (but could
 > be wrong) that as I repeated a test with the 1.1 bits that the same
 > CPU would be interrupted, but with 1.2 it seems that the
 > card/firmware/whatever is deciding to migrate interrupts around.

I don't think this is an OFED change but rather a kernel change.

Anyway, first make sure you don't have a userspace irq balancer
running.  (irqbalanced or something like that).

Then you can set IRQ affinity through 

    /proc/irq/77/smp_affinity

The file takes a bitmap of allowed CPUs.
(where 77 is your real IRQ number of course).

 - R.