bind-ethernet-ints-to-node.sh

#!/bin/bash

# Author: Andrew Theurer atheurer@redhat.com
# This script disables irqbalance and then for each network device,
# binds each interrupt to a node local cpu, iterating over the node
# local cpus for that device.

echo checking if irqbalance is running
if ps aux | pgrep irqbalance; then
	if [ -x /usr/bin/systemctl ]; then
		echo Using systemctl to stop irqbalanced
		systemctl stop irqbalance.service
	else
		echo Using service to stop irqbalanced
		service irqbalanced stop
	fi
else
	echo irqbalance is already disabled
fi

pushd /sys/class/net
j=0;
for dev in `/bin/ls`; do
	if [ -e $dev/device/msi_irqs ]; then
		# get array of node local cpus
		cpus=""
		cpulist=`cat $dev/device/local_cpulist`
		# a cpulist can have combinations of "x,y" and "m-n"
		for sublist in `echo $cpulist | sed -e 's/,/ /g'`; do
			# echo sublist: $sublist
			if echo $sublist | grep -q -- -; then
				first=`echo $sublist | awk -F- '{print $1}'`
				last=`echo $sublist | awk -F- '{print $2}'`
				cpus="$cpus `seq $first $last`"
			else
				cpus="$cpus $sublist"
			fi
		done
		cpuarray=($cpus)
		nr_cpus=${#cpuarray[*]}
		for irq in `/bin/ls $dev/device/msi_irqs`; do
			if [ -e /proc/irq/$irq ]; then
				cpu_idx=`echo "$j % $nr_cpus" | bc`
				echo ${cpuarray[$cpu_idx]} >/proc/irq/$irq/smp_affinity_list
				echo dev: $dev IRQ: $irq desired_cpu:${cpuarray[$cpu_idx]} actual_cpu:`cat /proc/irq/$irq/smp_affinity_list`
				let j=$j+1
			fi
		done
	fi
done
popd