先来看一下问题, 我们通过 ifconfig 查看接口的名称 为 p15p1, 一般机器为 eth0

再通过命令

➜  ~ cat /proc/interrupts | head -n 1 && cat /proc/interrupts |grep p15p1            CPU0       CPU1       CPU2       CPU3       CPU4       CPU5       CPU6       CPU7        130:    6235174          0          0          0          0          0          0          0   PCI-MSI 3145728-edge      p15p1

我们看到全部的网卡中断都集中到了 CPU0, 因此在有巨大网络流量的时候CPU0可能过载, 让网卡的数据包收发出现延迟. 为了分散CPU处理网卡中断, 我们需要设把网卡绑定到特定的CPU核心. (我的服务器因为只有一个网卡, 一般2U的机架服务器都有4个网卡, 绑定到不同的CPU核心.)

中断亲和性设置是通过掩码来标记的, 假设我们有一个8核心的CPU, 那么掩码为 11111111, 从左到右分别为 CPU0..CPU7, 位置关系如下:

1 1 1 1 1 1 1 1- - - - - - - - 7 6 5 4 3 2 1 0

设置中断亲和性的SHELL脚本

# !/bin/bash# # Copyright (c) 2014, 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  # # to get help:# set_irq_affinityusage(){    echo    echo "Usage: $0 [-x|-X] {all|local|remote|one|custom} [ethX] "    echo "    options: -x        Configure XPS as well as smp_affinity"    echo "    options: -X        Disable XPS but set 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}usageX(){    echo "options -x and -X cannot both be specified, pick one"    exit 1}if [ "$1" == "-x" ]; then    XPS_ENA=1    shiftfiif [ "$1" == "-X" ]; then    if [ -n "$XPS_ENA" ]; then        usageX    fi    XPS_DIS=2    shiftfiif [ "$1" == -x ]; then    usageXfiif [ -n "$XPS_ENA" ] && [ -n "$XPS_DIS" ]; then    usageXfiif [ -z "$XPS_ENA" ]; then    XPS_ENA=$XPS_DISfinum='^[0-9]+$'# VarsAFF=$1shiftcase "$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 modeesac# append the interfaces listed to the string with spaceswhile [ "$# " -ne "0" ] ; do    IFACES+=" $1"    shiftdone# for now the user must specify interfacesif [ -z "$IFACES" ]; then    usage    exit 1fi# support functionsset_affinity(){    VEC=$core    if [ $VEC -ge 32 ]    then        MASK_FILL=""        MASK_ZERO="00000000"        let "IDX = $VEC / 32"        for ((i=1; i /proc/irq/$IRQ/smp_affinity    printf "%s %d %s -> /proc/irq/$IRQ/smp_affinity\n" $IFACE $core $MASK    case "$XPS_ENA" in    1)        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    ;;    2)        MASK=0        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-$((n-1))/xps_cpus    ;;    *)    esac}# Allow usage of , or -# parse_range () {        RANGE=${@//,/ }        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 $IFACESCORES=$(https://gist.github.com/SaveT...把一个网卡绑定到特定的CPU核心.

root@ubuntu:~# ./set_irq_affinity.sh one 6 p15p1
IFACE CORE MASK -> FILE

p15p1 6 40 -> /proc/irq/130/smp_affinity
WARNING: irqbalance is running and will
likely override this script's affinitization.
Please stop the irqbalance service and/or execute
'killall irqbalance'

注意输出

IFACE CORE MASK -> FILE

p15p1 6 40 -> /proc/irq/130/smp_affinity

系统默认有中断负载均衡的进程, 如果是手工绑定, 需要停止它

killall irqbalance

查看结果

➜ ~ cat /proc/interrupts | head -n 1 && cat /proc/interrupts |grep p15p1

在一个终端中监控, 在另一个终端中设置

监控

watch -n 1 cat /proc/interrupts | head -n 1 && cat /proc/interrupts |grep p15p1

设置

./set_irq_affinity.sh one 1 p15p1
./set_irq_affinity.sh one 2 p15p1
./set_irq_affinity.sh one 3 p15p1

可以看到中断数的增长,从CPU1到CPU2,再到CPU3(注意CPU编号从0开始的, 8核的CPU编号是0-7)#linux、network#

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