On Tuesday, April 24, 2012 8:11:07 pm Sean Bruno wrote: > http://people.freebsd.org/~sbruno/if_igb.c.txt > > Scenario I've just seen: > > 8 core machine > 2 igb(4) interfaces > set num_queues=4 > > igb0:0 --> cpu0 > igb0:1 --> cpu1 > igb0:2 --> cpu2 > igb0:3 --> cpu3 > > igb1:0 --> cpu0 > igb1:1 --> cpu1 > igb1:2 --> cpu2 > igb1:3 --> cpu3 > > I suspect, that we need a static global to keep track of what cpu last > was last bound to a queue. My patch does do this, but I don't know if > its the right thing. > > Since I'm doing multiple interfaces, I need to make sure I don't > schedule a queue to a non existent cpu, so take a modulo of the counter > and the number of cpus in the box. > > Perhaps not the most elegant solution, but its a thing?
CPU IDs are not guaranteed to be dense. However, you can use CPU_FIRST() and CPU_NEXT() with your static global instead. OTOH, if igb were to just leave the interrupts alone instead of binding them by hand, they would get round-robin assigned among available cores already. I think in this case the best approach might be to add a tunable to disable igb's manual binding and instead let the default system round-robin be preserved. -- John Baldwin _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
