irq_balance_habrahabr.sh

irq_balance_habrahabr_POSIX.sh

#!/bin/sh

# checkbashisms irq_balance_habrahabr_POSIX.sh
# from http://habrahabr.ru/post/108240/
ncpus=$(grep -ciw ^processor /proc/cpuinfo)
[ $ncpus -gt 1 ] || exit 1

n=0
for irq in `awk '/eth/{gsub(":","",$0);print $1}' /proc/interrupts`; do
	f="/proc/irq/$irq/smp_affinity"
	[ -w "$f" ] || continue
	cpu=$(($ncpus-($n%$ncpus)-1))
	if [ $cpu -ge 0 ]; then
		mask=$(printf %x $(echo $cpu | awk '{print 2^$0}'))
		echo "Assign SMP affinity: eth queue $n, irq $irq, cpu $cpu, mask 0x$mask"
		echo "$mask" > "$f"
		n=$(($n+1))
	fi
done

Now POSIX compliant.