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- 2020-03-15
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irqstats
Name
irqstats - Munin plugin to monitor individual interrupts on a Linux machine
Applicable Systems
Any Linux system
Configuration
None needed
Usage
Link this plugin to @@CONFDIR@@/plugins/ and restart the munin-node.
Interpretation
The plugin simply shows the number of interrupts on each interrupt line. The lines are identified by the attached equipment rather than the IRQ numbers.
High interrupt rates may coincide with high loads on disk, network or other I/O, this is normal.
Magic Markers
#%# family=auto
#%# capabilities=autoconf
Bugs
None known
Author
Unknown
License
GPLv2
#!@@PERL@@ -w
# -*- cperl -*-
use strict;
use warnings;
=head1 NAME
irqstats - Munin plugin to monitor individual interrupts on a Linux machine
=head1 APPLICABLE SYSTEMS
Any Linux system
=head1 CONFIGURATION
None needed
=head1 USAGE
Link this plugin to @@CONFDIR@@/plugins/ and restart the munin-node.
=head1 INTERPRETATION
The plugin simply shows the number of interrupts on each interrupt
line. The lines are identified by the attached equipment rather than
the IRQ numbers.
High interrupt rates may coincide with high loads on disk, network or
other I/O, this is normal.
=head1 MAGIC MARKERS
#%# family=auto
#%# capabilities=autoconf
=head1 BUGS
None known
=head1 AUTHOR
Unknown
=head1 LICENSE
GPLv2
=cut
use Munin::Plugin;
if (defined $ARGV[0] && $ARGV[0] eq 'autoconf') {
if(-r '/proc/interrupts') {
print "yes\n";
exit(0);
} else {
print "no (file /proc/interrupts not readable)\n";
exit(1);
}
}
my $sun;
$sun = 1 if (`uname -m` =~ /sparc/);
my $in;
my @cpus;
my $cpus;
if ($sun) {
@cpus = grep (/^cpu\d+/, `cat /proc/stat`);
$cpus = scalar @cpus;
} else {
open $in, '<', '/proc/interrupts'
or die "Can't open /proc/interrupts: $!\n";
@cpus = split(' ', <$in>);
$cpus = scalar @cpus;
}
my $cpu;
if ($0 =~ /(?:.*\/)?irqstats_(.+)/) {
$cpu = $1;
if ($cpu > $#cpus) {
die "Requested CPU $cpu out of bounds (0..$#cpus)\n";
}
}
my @irqs;
sub sum (@) {
my $sum = 0;
$sum += $_ || 0 for @_; # Avoid complaints about empty strings
return $sum;
}
while (my $line = <$in>) {
my ($irq, $label, $type);
my @data;
if ($sun) {
@data = split (' ', $line, $cpus + 2);
} else {
@data = split(' ', $line, $cpus + 3);
}
chomp @data;
$irq = shift @data;
next unless defined($irq) and length $irq;
chop $irq;
if ($irq =~ /^\d+$/) {
# For numbered interrupts the format is set
$label = pop @data;
$type = pop @data;
# work around "MPIC \d" on powerpc
if ($type =~ "MPIC" && $label =~ s/^([12])\s+//) {
$type .= " $1";;
}
# handle hwirq
if ($label =~ /^(\d+)\s+(.+)/) {
$label = $1 eq $irq ? $2 : "$2 [$1]";
}
# handle level/edge
$label =~ s/^(Level|Edge)\s+//;
} else {
# For named interrupts it's more confusing, slice and dice
# to divorce data from commentary
$label = join(" ",@data[$cpus..$#data]);
@data = @data[0..$cpus-1];
}
# Skip non-per-cpu values for per-cpu stats
# This will ignore ERR: and MIS: lines on multi cpu systems
# (checked on 2.6.22, 2.6.24)
# next if defined($cpu) and $cpus > @data;
push @irqs, {
irq => $irq,
label => $label,
count => defined($cpu) ? $data[$cpu] : sum(@data)
};
}
close $in;
if (defined $ARGV[0] && $ARGV[0] eq 'config') {
print 'graph_title Individual interrupts',
defined($cpu) ? " on CPU $cpu\n" : "\n";
print <<EOM;
graph_args --base 1000 --logarithmic
graph_vlabel interrupts / \${graph_period}
graph_category system
graph_info Shows the number of different IRQs received by the kernel. High disk or network traffic can cause a high number of interrupts (with good hardware and drivers this will be less so). Sudden high interrupt activity with no associated higher system activity is not normal.
EOM
print join(' ', 'graph_order', map {"i" . $_->{irq}} @irqs), "\n";
for my $irq (@irqs) {
my $f = ($irq->{label} || $irq->{irq});
$f = $irq->{irq} if (length ($f) > 47);
print "i", $irq->{irq}, '.label ', $f, "\n";
if ( $irq->{label} ) {
print "i", $irq->{irq}, '.info Interrupt ', $irq->{irq}, ', for device(s): ', $irq->{label}, "\n"
} elsif ( $irq->{irq} =~ /NMI/i ) {
print "i", $irq->{irq}, ".info Nonmaskable interrupt. Either 0 or quite high. If it's normaly 0 then just one NMI will often mark some hardware failure.\n";
} elsif ( $irq->{irq} =~ /LOC/i ) {
print "i", $irq->{irq}, ".info Local (pr. CPU core) APIC timer interrupt. Until 2.6.21 normaly 250 or 1000 pr second. On modern 'tickless' kernels it more or less reflects how busy the machine is.\n";
}
print "i", $irq->{irq}, ".type DERIVE\n";
print "i", $irq->{irq}, ".min 0\n";
print_thresholds("i$irq->{irq}");
}
} else {
print "i", $_->{irq}, '.value ', $_->{count}, "\n" for @irqs;
}
__END__