smp_affinity weirdness in LK 2.6.14
Hello,
I found that I cannot change IRQ affinity in the 2.6.14 kernel. It works however on the 2.6.13.4 and earlier.
2.6.13.4:
# cat /proc/irq/189/smp_affinity 1 # echo 2 > /proc/irq/189/smp_affinity # cat /proc/irq/189/smp_affinity 2 #
2.6.14:
# cat /proc/irq/189/smp_affinity 1 # echo 2 > /proc/irq/189/smp_affinity # cat /proc/irq/189/smp_affinity 1 # /proc/interrupts is also showing that all all IRQs are bound to CPU0. I must add, that this system is a P4 with HyperThreading support. I've tried both with CONFIG_IRQBALANCE=y and n but the result is always the same. With the new kernel I cannot balance the IRQs neither by hand, nor userspace/kernel tools. Is that normal?
Regards
-Dimitri
Quoted 5 lines · Dimitri Puzin
Hello,
I found that I cannot change IRQ affinity in the 2.6.14 kernel. It works however on the 2.6.13.4 and earlier.
This got fixed with 2.6.15-rc4
commit fe655d3a06488c8a188461bca493e9f23fc8c448
Author: Shaohua Li <[email protected]> Date: Tue Nov 29 19:34:42 2005 -0800
[PATCH] setting irq affinity is broken in ia32 with MSI enabled
Setting irq affinity stops working when MSI is enabled. With MSI, move_irq is empty, so we can't change irq affinity. It appears a typo in Ashok's original commit for this issue. X86_64 actually is using move_native_irq.
Signed-off-by Shaohua Li <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Linus Torvalds <[email protected]>
Regards,
-Dimitri Puzin aka Tristan-777