Lots of replies to a very old thread I created. I since found a better solution, a script from Intel that sets the irq affinities.
I invoke it thus on my machine (eth0 and eth1 are my WAN and WAN2 interfaces, since I have two internet links. eth3 is my LAN interface). It took a bit of experimentation to get the correct scheme - I recall that attempting to specify 1-6 on the eth3 LAN interface didn't give the right result, all though I can't remember why.
I got much better results out of this script than attempting to manually assign interrupt affinities.
/bin/bash -c "/usr/bin/set_irq_affinity 1-6 eth0"
/bin/bash -c "/usr/bin/set_irq_affinity 1-6 eth1"
/bin/bash -c "/usr/bin/set_irq_affinity eth3"
I deliberately don't balance interrupts on core 0 and core 7 as I have certain CPU hungry processes pinned to those cores. On my machine at least, this balances interrupts very nicely such that softirqs are pretty much evenly spread across all cores when maxing out SQM on a 1Gbps stream.
#!/bin/bash
#
# Copyright (c) 2015, Intel Corporation
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of Intel Corporation nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Affinitize interrupts to cores
#
# typical usage is (as root):
# set_irq_affinity -x local eth1 <eth2> <eth3>
#
# to get help:
# set_irq_affinity
usage()
{
echo
echo "Usage: $0 [-x] {all|local|remote|one|custom} [ethX] <[ethY]>"
echo " options: -x Configure XPS as well as smp_affinity"
echo " options: {remote|one} can be followed by a specific node number"
echo " Ex: $0 local eth0"
echo " Ex: $0 remote 1 eth0"
echo " Ex: $0 custom eth0 eth1"
echo " Ex: $0 0-7,16-23 eth0"
echo
exit 1
}
if [ "$1" == "-x" ]; then
XPS_ENA=1
shift
fi
num='^[0-9]+$'
# Vars
AFF=$1
shift
case "$AFF" in
remote) [[ $1 =~ $num ]] && rnode=$1 && shift ;;
one) [[ $1 =~ $num ]] && cnt=$1 && shift ;;
all) ;;
local) ;;
custom) ;;
[0-9]*) ;;
-h|--help) usage ;;
"") usage ;;
*) IFACES=$AFF && AFF=all ;; # Backwards compat mode
esac
# append the interfaces listed to the string with spaces
while [ "$#" -ne "0" ] ; do
IFACES+=" $1"
shift
done
# for now the user must specify interfaces
if [ -z "$IFACES" ]; then
usage
exit 1
fi
# support functions
set_affinity()
{
VEC=$core
if [ ${VEC} -eq 32 ]
then
MASK_FILL=""
MASK_ZERO="00000000"
let "IDX = $VEC / 32"
for ((i=1; i<=$IDX;i++))
do
MASK_FILL="${MASK_FILL},${MASK_ZERO}"
done
let "VEC -= 32 * $IDX"
MASK_TMP=$((1<<$VEC))
MASK=$(printf "%X%s" $MASK_TMP $MASK_FILL)
else
MASK_TMP=$((1<<$VEC))
MASK=$(printf "%X" $MASK_TMP)
fi
printf "%s" $MASK > /proc/irq/$IRQ/smp_affinity
printf "%s %d %s -> /proc/irq/$IRQ/smp_affinity\n" $IFACE $core $MASK
if ! [ -z "$XPS_ENA" ]; then
printf "%s %d %s -> /sys/class/net/%s/queues/tx-%d/xps_cpus\n" $IFACE $core $MASK $IFACE $((n-1))
printf "%s" $MASK > /sys/class/net/$IFACE/queues/tx-$((n-1))/xps_cpus
fi
}
# Allow usage of , or -
#
parse_range () {
RANGE=${@//,/ }
RANGE=${RANGE//-/..}
LIST=""
for r in $RANGE; do
# eval lets us use vars in {#..#} range
[[ $r =~ '..' ]] && r="$(eval echo {$r})"
LIST+=" $r"
done
echo $LIST
}
# Affinitize interrupts
#
setaff()
{
CORES=$(parse_range $CORES)
ncores=$(echo $CORES | wc -w)
n=1
# this script only supports interrupt vectors in pairs,
# modification would be required to support a single Tx or Rx queue
# per interrupt vector
queues="${IFACE}-.*TxRx"
irqs=$(grep "$queues" /proc/interrupts | cut -f1 -d:)
[ -z "$irqs" ] && irqs=$(grep $IFACE /proc/interrupts | cut -f1 -d:)
[ -z "$irqs" ] && irqs=$(for i in `ls -Ux /sys/class/net/$IFACE/device/msi_irqs` ;\
do grep "$i:.*TxRx" /proc/interrupts | grep -v fdir | cut -f 1 -d : ;\
done)
[ -z "$irqs" ] && echo "Error: Could not find interrupts for $IFACE"
echo "IFACE CORE MASK -> FILE"
echo "======================="
for IRQ in $irqs; do
[ "$n" -gt "$ncores" ] && n=1
j=1
# much faster than calling cut for each
for i in $CORES; do
[ $((j++)) -ge $n ] && break
done
core=$i
set_affinity
((n++))
done
}
# now the actual useful bits of code
# these next 2 lines would allow script to auto-determine interfaces
#[ -z "$IFACES" ] && IFACES=$(ls /sys/class/net)
#[ -z "$IFACES" ] && echo "Error: No interfaces up" && exit 1
# echo IFACES is $IFACES
CORES=$(</sys/devices/system/cpu/online)
[ "$CORES" ] || CORES=$(grep ^proc /proc/cpuinfo | cut -f2 -d:)
for IFACE in $IFACES; do
# echo $IFACE being modified
dev_dir=/sys/class/net/$IFACE/device
[ -e $dev_dir/numa_node ] && node=$(<$dev_dir/numa_node)
[ "$node" ] && [ "$node" -gt 0 ] || node=0
case "$AFF" in
one)
[ -n "$cnt" ] || cnt=0
CORES=$cnt
;;
all)
CORES=$CORES
;;
custom)
echo -n "Input cores for $IFACE (ex. 0-7,15-23): "
read CORES
;;
[0-9]*)
CORES=$AFF
;;
*)
usage
exit 1
;;
esac
# call the worker function
setaff
done
# 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
Running a speedtest:
