QLogic OFED+ Host Software User Guide, Rev. B

F–Troubleshooting
Performance Issues
Next, find the IRQ number and bind it to a CPU. The IRQ number can be found in
one of two ways, depending on the system used. Both methods are described in
the following paragraphs.
NOTE:
Take care when cutting and pasting commands from PDF documents, as
quotes are special characters and may not be translated correctly.
Method 1
Check to see if the IRQ number is found in /proc/irq/xxx, where xxx is the
IRQ number in /sys/class/infiniband/ipath*/device/irq. Do this as a
root user. For example:
# my_irq=‘cat /sys/class/infiniband/ipath*/device/irq‘
# ls /proc/irq
If $my_irq can be found under /proc/irq/, then type:
# echo 01 > /proc/irq/$my_irq/smp_affinity
Method 2
If command from Method 1, ls /proc/irq, cannot find $my_irq, then use the
following commands instead:
# my_irq=‘cat /proc/interrupts|grep ib_qib|awk \
’{print $1}’|sed -e ’s/://’‘
# echo 01 > /proc/irq/$my_irq/smp_affinity
This method is not the first choice because, on some systems, there may be two
rows of ib_qib output, and you will not know which one of the two numbers to
choose. However, if you cannot find $my_irq listed under /proc/irq
(Method 1), this type of system most likely has only one line for ib_qib listed in
/proc/interrupts, so you can use Method 2.
Here is an example:
# cat /sys/class/infiniband/ipath*/device/irq
98
# ls /proc/irq
0 10 11 13 15 233 4 50 7 8 90
1 106 12 14 2 3 5 58 66 74 9
(Note that you cannot find 98.)
# cat /proc/interrupts|grep ib_qib|awk \
’{print $1}’|sed -e ’s/://’
106
# echo 01 > /proc/irq/106/smp_affinity
Using the echo command immediately changes the processor affinity of an IRQ.
F-10 D000046-005 B