distribute hardware interrupts from Ethernet devices by CPU cores.

irq2smp.sh

#!/bin/bash
#
#  irq2smp -- distribute hardware interrupts from Ethernet devices by CPU cores.
#
#  Should be called from /etc/rc.local.
#

ncpus=`grep -ciw ^processor /proc/cpuinfo`
netmask="(eth|wan)"
test "$ncpus" -gt 1 || exit 1

n=0
for irq in `cat /proc/interrupts | grep -E $netmask | 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 ** $cpu]`
        echo "Assign SMP affinity: eth$n, irq $irq, cpu $cpu, mask 0x$mask"
        echo "$mask" > "$f"
        let n+=1
    fi
done

# if network cards doesn't support MSI-X multiple queues
if [ $n -lt 4 ]; then
	cpus=$(printf %x $[ 2 ** $ncpus - 1 ])
	for iface in `ls -1 /sys/class/net/ | grep -E $netmask`; do
		if [ ! -f /sys/class/net/$iface/queues/rx-0/rps_cpus ]; then
			echo "`file /sys/class/net/$iface/queues/rx-0/rps_cpus`"
		else
			echo "Assign RPS $cpus to $iface"
			echo "$cpus" > /sys/class/net/$iface/queues/rx-0/rps_cpus
		fi
	done
fi

for i in `ls /sys/class/net | grep -E $netmask`; do
  # /sys/class/net/eth0/queues/rx-0/rps_flow_cnt
  [ ! -d /sys/class/net/$i ] && continue
  echo "set rps_flow_cnt=32768 for $i"
  echo 32768 > /sys/class/net/$i/queues/rx-0/rps_flow_cnt
done
echo 32768 > /proc/sys/net/core/rps_sock_flow_entries