#!/bin/bash
#
# Sets the CPU affiniy of the IRQ handling inbound messages on the given
# network interface

IFACE=$1
AFFINITY=$2

if [ -z "$IFACE" -o -z "$AFFINITY" ]
then
	exit 1
fi

PCI_ADDR=$(ethtool -i ${IFACE} | grep bus-info | sed -e 's/bus-info: //')
if [ -z "$PCI_ADDR" ]
then
	exit 2
fi

IRQ=$(grep "MSIX-${PCI_ADDR}.*input" /proc/interrupts | awk -F ':' '{print $1}' | awk '{print $1}')
if [ -z "$IRQ" ]
then
	exit 3
fi

PREV=$(cat /proc/irq/${IRQ}/smp_affinity_list)
echo "Setting affinity for IRQ ${IRQ} of ${IFACE}@${PCI_ADDR} to ${AFFINITY}, was ${PREV}"
echo ${AFFINITY} > /proc/irq/${IRQ}/smp_affinity_list