On Wed, 5 Jul 2017, Chen Yu wrote: > On Tue, Jul 04, 2017 at 10:50:33AM +0200, Thomas Gleixner wrote: > Here's the test result for affinity: > # uname -r > 4.12.0+ > # cat /proc/irq/32/smp_affinity > 00000000,80000000 > # echo 0 > /sys/devices/system/cpu/cpu31/online > # cat /proc/irq/32/smp_affinity > 00000000,ffffffff > Looks like cpu31 is till included in the irq mask.
Yes, because the offline broke affinity and now it's reset to the default affinity mask. /proc/irq/*/affinity is the affinity which is allowed by the admin, not the one which is effective. Look at /proc/irq/32/effective_affinity to see where it's really routed to. Thanks, tglx