set_irq_affinity.sh

#!/bin/bash

# setting up irq affinity according to /proc/interrupts
# 2008-11-25 Robert Olsson
# 2009-02-19 updated by Jesse Brandeburg
#
# > Dave Miller:
# (To get consistent naming in /proc/interrups)
# I would suggest that people use something like:
#   char buf[IFNAMSIZ+6];
#
#   sprintf(buf, "%s-%s-%d",
#           netdev->name,
#       (RX_INTERRUPT ? "rx" : "tx"),
#       queue->index);
#
#  Assuming a device with two RX and TX queues.
#  This script will assign: 
#
#   eth0-rx-0  CPU0
#   eth0-rx-1  CPU1
#   eth0-tx-0  CPU0
#   eth0-tx-1  CPU1
#

set_affinity()
{
    MASK=$((1<<$VEC))
    printf "%s mask=%X for /proc/irq/%d/smp_affinity\n" $DEV $MASK $IRQ
    printf "%X" $MASK > /proc/irq/$IRQ/smp_affinity
    #echo $DEV mask=$MASK for /proc/irq/$IRQ/smp_affinity
    #echo $MASK > /proc/irq/$IRQ/smp_affinity
}

if [ "$1" = "" ] ; then
    echo "Description:"
    echo "    This script attempts to bind each queue of a multi-queue NIC"
    echo "    to the same numbered core, ie tx0|rx0 --> cpu0, tx1|rx1 --> cpu1"
    echo "usage:"
    echo "    $0 eth0 [eth1 eth2 eth3]"
fi


# check for irqbalance running
IRQBALANCE_ON=`ps ax | grep -v grep | grep -q irqbalance; echo $?`
if [ "$IRQBALANCE_ON" == "0" ] ; then
    echo " WARNING: irqbalance is running and will"
    echo "          likely override this script's affinitization."
    echo "          Please stop the irqbalance service and/or execute"
    echo "          'killall irqbalance'"
fi

#
# Set up the desired devices.
#

for DEV in $*
do
  for DIR in rx tx TxRx
  do
     MAX=`grep $DEV-$DIR /proc/interrupts | wc -l`
     if [ "$MAX" == "0" ] ; then
       MAX=`egrep -i "$DEV:.*$DIR" /proc/interrupts | wc -l`
     fi
     if [ "$MAX" == "0" ] ; then
       echo no $DIR vectors found on $DEV
       continue
       #exit 1
     fi
     for VEC in `seq 0 1 $MAX`
     do
        IRQ=`cat /proc/interrupts | grep -i $DEV-$DIR-$VEC"$"  | cut  -d:  -f1 | sed "s/ //g"`
        if [ -n  "$IRQ" ]; then
          set_affinity
        else
           IRQ=`cat /proc/interrupts | egrep -i $DEV:v$VEC-$DIR"$"  | cut  -d:  -f1 | sed "s/ //g"`
           if [ -n  "$IRQ" ]; then
             set_affinity
           fi
        fi
     done
  done
done