IRQ设置CPU亲和的几个注意事项

一、查看IRQ

cat /proc/interrupts

    命令执行结果的第一列，就是设备对应的irq号（irqno）。

二、查看IRQ亲和

cat /proc/irq/$irqno/smp_affinity

    或者

cat /proc/irq/$irqno/smp_affinity_list

    这两个文件相互联动，即：内容相同，描述方式不同；修改一个，则另一个相应变化。

三、设置IRQ亲和

echo ff > /proc/irq/$irqno/smp_affinity

或者

echo 0,1 > /proc/irq/$irqno/smp_affinity_list
OR
echo 0-2 > /proc/irq/$irqno/smp_affinity_list

    *注意：设置IRQ亲和前，必须先关闭irqbalance，否则设置无效。

四、一般网卡
    可以将一个网卡的IRQ，同时绑定到多个CPU，进行负载均衡，效果如下：


五、多队列网卡
   
    图是Intel 82575硬件逻辑图。通过Hash网络四元组，将一条流放到相同的队列，及该队列绑定的中断。如果数据都来自于同一条流，有相同的四元组，则无法达到负载均衡的目的。
    一个队列的IRQ，无法绑定到多个CPU。
    均衡后效果如下：


六、附：管理irq亲和的脚本

#!/usr/bin/perl
#
# =====================================================================================
# Filenamei : irqmgr.sh
#
# Description :
#
# Version : 0.1.0
# Created : Mon Sep 5 16:18:06 2016
# Author : zhonghaohua
# Mail : [e-mail]
#
# Change log :
# =====================================================================================
#

$_name = 'irqmgr';
$_version = 'ver0.1.0';
$_author = '[e-mail]';

#BEGIN
if( $ARGV[0] eq 'show') {
    if( @ARGV == 1) {
        &show( 'all');
    }
    elsif( @ARGV == 2) {
        &show( $ARGV[1]);
    }
    else {
        &help;
    }
}
elsif( $ARGV[0] eq 'set') {
    if( @ARGV == 2 || @ARGV == 3) {
        shift( @ARGV);
        &set( @ARGV);
    }
    else {
        &help;
    }
}
else {
    &help;
}

exit;
#END

sub help {
    print $_name." ".$_version." ".$_author."\n\n";

    print "Usage:";
    print "\t$_name show all\n";
    print "\t$_name show eth0\n";
    print "\t$_name set eth\n";
    print "\t$_name set eth0 [0-3|0,1,2,3]\n";
    print "\t$_name (print this help information)\n";
    print "\n";
}

sub set {
    my( $devname, $cpus) = @_;

    if(    !&check_irqbalance) {
        return;
    }

    @irqlist = &get_irqlist( $devname, 0);

    $cpucnt = &cnt_cpus();
    $irqcnt = @irqlist;

    print "Startup settings: ";

    if( $cpucnt * 2 < $irqcnt) {
        print "\33[1m\33[31m";
    }
    elsif( $cpucnt < $irqcnt) {
        print "\33[1m\33[33m";
    }
    else {
        print "\33[1m\33[32m";
    }

    print "\33[0m\n";

    for( $i = 0; $i < @irqlist; $i++) {

        $loop = 1;
        while( $loop) {

            $r = "[$irqlist[$i][0], $irqlist[$i][1]] ";
            $cpumask = `cat /proc/irq/$irqlist[$i][0]/smp_affinity`;
            chomp( $cpumask);
            $cpulist = `cat /proc/irq/$irqlist[$i][0]/smp_affinity_list`;
            chomp( $cpulist);
            print $r."running-config: mask[".$cpumask."] cpu[".$cpulist."]\n";

            print "\twould you want to set (CPUMask/Next/Quit):";
            chomp( $_ = <STDIN>);
            if( /(^[0-9a-fA-F]+)/) {
                `echo $1 >> /proc/irq/$irqlist[$i][0]/smp_affinity`;
            }
            elsif( /^[nN]/) {
                $loop = 0;
            }
            elsif( /^[qQeE]/) {
                return;
            }
            else {
                print "\33[1m\33[33m\t$_ is an invalid value for the CPUMask.\33[0m\n";
            }
        }
    }
}

sub show {
    my( $devname, ) = @_;

    @irqlist = &get_irqlist( $devname, 1);
    &show_irqlist( @irqlist);
}

sub get_irqlist {
    my( $devname, $flag_display) = @_;

    if( $devname eq 'all') {
        @irqrequest = split( /\n/, `cat /proc/interrupts`);
    }
    else {
        @irqrequest = split( /\n/, `cat /proc/interrupts |grep $devname`);
    }

    $i = 0;
    foreach( @irqrequest) {
        if( $flag_display == 1) {
            print $_."\n";
        }

        if( /(\d+):(\s+\S+){9}\s+(\S+)/ ) {
            $irqlist[$i][0] = $1;
            $irqlist[$i][1] = $3;
            $i++;
        }
    }

    return @irqlist;
}

sub show_irqlist {
    $i = 0;
    foreach( @_) {
        $r = "[$_[$i][0], $_[$i][1]] ";
        $cmd1 = `cat /proc/irq/$_[$i][0]/smp_affinity`;
        chomp($cmd1);
        $cmd2 = `cat /proc/irq/$_[$i][0]/smp_affinity_list`;
        chomp($cmd2);

        print $r."running-config: mask[".$cmd1."] cpu[".$cmd2."]\n";
        $i++;
    }
}

sub check_irqbalance {
    @result = `ps aux|grep irqbalance`;
    $isworking = 0;

    foreach( @result) {
        if( !(/grep/)) {
            $isworking = 1;
        }
    }

    if( $isworking) {
        print "\33[1m\33[33mirqbalance is running, would you want to stop?\33[0m[Yes/No]:";
        chomp( $_ = <STDIN>);
        if( /yes/i) {
            `killall irqbalance`;
            &delay(2);
            print "\33[1m\33[32mirqbalance is stoped.\33[0m\n\n";
            return 1;
        }
        else {
            return 0;
        }
    }

    return 1;
}

sub cnt_cpus {
    @cpuinfo = split( /\n/, `cat /proc/cpuinfo |grep processor`);
    foreach( @cpuinfo) {
        $_ =~ /(\d+)$/;
        $cpucnt = $1;
    }

    return $cpucnt;
}

sub delay {
    my($interval, ) = @_;

    $total = $interval * 1000 * 1000;
    $t = 200 * 1000;

    for( ; $total > 0; $total -= $t) {
        print '.';
        `usleep $t`;
    }

    print ' ';
}



#ENDFILE

END.