irq_balance_habrahabr.sh

irq_balance_habrahabr.sh

#!/bin/bash

# from http://habrahabr.ru/post/108240/
ncpus=`grep -ciw ^processor /proc/cpuinfo`
test "$ncpus" -gt 1 || exit 1

n=0
for irq in `cat /proc/interrupts | grep eth | awk '{print $1}' | sed s/\://g`
do
    f="/proc/irq/$irq/smp_affinity"
    test -r "$f" || continue
    cpu=$[$ncpus - ($n % $ncpus) - 1]
    if [ $cpu -ge 0 ]
            then
                mask=`printf %x $[2 ** $cpu]`
                echo "Assign SMP affinity: eth queue $n, irq $irq, cpu $cpu, mask 0x$mask"
                echo "$mask" > "$f"
                let n+=1
    fi
done

$ cat /proc/irq/*/smp_affinityff
0f
0f
0f
0f
0f
0f
0c

$ echo $[2 ** 0] $[2 ** 1] $[2 ** 2] $[2 ** 3]
1 2 4 8

$ printf '%02x %02x %02x %02x' "$[2 ** 0]" "$[2 ** 1]" "$[2 ** 2]" "$[2 ** 3]"
01 02 04 08