/usr/share/perl5/Sys/Statistics/Linux/DiskStats.pm is in libsys-statistics-linux-perl 0.66-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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Sys::Statistics::Linux::DiskStats - Collect linux disk statistics.
=head1 SYNOPSIS
use Sys::Statistics::Linux::DiskStats;
my $lxs = Sys::Statistics::Linux::DiskStats->new;
$lxs->init;
sleep 1;
my $stat = $lxs->get;
Or
my $lxs = Sys::Statistics::Linux::DiskStats->new(initfile => $file);
$lxs->init;
my $stat = $lxs->get;
=head1 DESCRIPTION
Sys::Statistics::Linux::DiskStats gathers disk statistics from the virtual F</proc> filesystem (procfs).
For more information read the documentation of the front-end module L<Sys::Statistics::Linux>.
=head1 DISK STATISTICS
Generated by F</proc/diskstats> or F</proc/partitions>.
major - The mayor number of the disk
minor - The minor number of the disk
rdreq - Number of read requests that were made to physical disk per second.
rdbyt - Number of bytes that were read from physical disk per second.
wrtreq - Number of write requests that were made to physical disk per second.
wrtbyt - Number of bytes that were written to physical disk per second.
ttreq - Total number of requests were made from/to physical disk per second.
ttbyt - Total number of bytes transmitted from/to physical disk per second.
=head1 METHODS
=head2 new()
Call C<new()> to create a new object.
my $lxs = Sys::Statistics::Linux::DiskStats->new;
Maybe you want to store/load the initial statistics to/from a file:
my $lxs = Sys::Statistics::Linux::DiskStats->new(initfile => '/tmp/diskstats.yml');
If you set C<initfile> it's not necessary to call sleep before C<get()>.
It's also possible to set the path to the proc filesystem.
Sys::Statistics::Linux::DiskStats->new(
files => {
# This is the default
path => '/proc',
diskstats => 'diskstats',
partitions => 'partitions',
}
);
=head2 init()
Call C<init()> to initialize the statistics.
$lxs->init;
=head2 get()
Call C<get()> to get the statistics. C<get()> returns the statistics as a hash reference.
my $stat = $lxs->get;
=head2 raw()
Get raw values.
=head1 EXPORTS
No exports.
=head1 SEE ALSO
B<proc(5)>
=head1 REPORTING BUGS
Please report all bugs to <jschulz.cpan(at)bloonix.de>.
=head1 AUTHOR
Jonny Schulz <jschulz.cpan(at)bloonix.de>.
=head1 COPYRIGHT
Copyright (c) 2006, 2007 by Jonny Schulz. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
=cut
package Sys::Statistics::Linux::DiskStats;
use strict;
use warnings;
use Carp qw(croak);
use Time::HiRes;
our $VERSION = '0.24';
sub new {
my $class = shift;
my $opts = ref($_[0]) ? shift : {@_};
my %self = (
files => {
path => '/proc',
diskstats => 'diskstats',
partitions => 'partitions',
},
# --------------------------------------------------------------
# The sectors are equivalent with blocks and have a size of 512
# bytes since 2.4 kernels. This value is needed to calculate the
# amount of disk i/o's in bytes.
# --------------------------------------------------------------
blocksize => 512,
);
if (defined $opts->{initfile}) {
require YAML::Syck;
$self{initfile} = $opts->{initfile};
}
foreach my $file (keys %{ $opts->{files} }) {
$self{files}{$file} = $opts->{files}->{$file};
}
if ($opts->{blocksize}) {
$self{blocksize} = $opts->{blocksize};
}
return bless \%self, $class;
}
sub init {
my $self = shift;
if ($self->{initfile} && -r $self->{initfile}) {
$self->{init} = YAML::Syck::LoadFile($self->{initfile});
$self->{time} = delete $self->{init}->{time};
} else {
$self->{time} = Time::HiRes::gettimeofday();
$self->{init} = $self->_load;
}
}
sub get {
my $self = shift;
my $class = ref $self;
if (!exists $self->{init}) {
croak "$class: there are no initial statistics defined";
}
$self->{stats} = $self->_load;
$self->_deltas;
if ($self->{initfile}) {
$self->{init}->{time} = $self->{time};
YAML::Syck::DumpFile($self->{initfile}, $self->{init});
}
return $self->{stats};
}
sub raw {
my $self = shift;
my $raw = $self->_load;
return $raw;
}
#
# private stuff
#
sub _load {
my $self = shift;
my $class = ref $self;
my $file = $self->{files};
my $bksz = $self->{blocksize};
my (%stats, $fh);
# -----------------------------------------------------------------------------
# one of the both must be opened for the disk statistics!
# if diskstats (2.6) doesn't exists then let's try to read
# the partitions (2.4)
#
# /usr/src/linux/Documentation/iostat.txt shortcut
#
# ... the statistics fields are those after the device name.
#
# Field 1 -- # of reads issued
# This is the total number of reads completed successfully.
# Field 2 -- # of reads merged, field 6 -- # of writes merged
# Reads and writes which are adjacent to each other may be merged for
# efficiency. Thus two 4K reads may become one 8K read before it is
# ultimately handed to the disk, and so it will be counted (and queued)
# as only one I/O. This field lets you know how often this was done.
# Field 3 -- # of sectors read
# This is the total number of sectors read successfully.
# Field 4 -- # of milliseconds spent reading
# This is the total number of milliseconds spent by all reads (as
# measured from __make_request() to end_that_request_last()).
# Field 5 -- # of writes completed
# This is the total number of writes completed successfully.
# Field 7 -- # of sectors written
# This is the total number of sectors written successfully.
# Field 8 -- # of milliseconds spent writing
# This is the total number of milliseconds spent by all writes (as
# measured from __make_request() to end_that_request_last()).
# Field 9 -- # of I/Os currently in progress
# The only field that should go to zero. Incremented as requests are
# given to appropriate request_queue_t and decremented as they finish.
# Field 10 -- # of milliseconds spent doing I/Os
# This field is increases so long as field 9 is nonzero.
# Field 11 -- weighted # of milliseconds spent doing I/Os
# This field is incremented at each I/O start, I/O completion, I/O
# merge, or read of these stats by the number of I/Os in progress
# (field 9) times the number of milliseconds spent doing I/O since the
# last update of this field. This can provide an easy measure of both
# I/O completion time and the backlog that may be accumulating.
# -----------------------------------------------------------------------------
my $file_diskstats = $file->{path} ? "$file->{path}/$file->{diskstats}" : $file->{diskstats};
my $file_partitions = $file->{path} ? "$file->{path}/$file->{partitions}" : $file->{partitions};
if (open $fh, '<', $file_diskstats) {
while (my $line = <$fh>) {
# -- -- -- F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11
# $1 $2 $3 $4 -- $5 -- $6 -- $7 -- -- -- --
if ($line =~ /^\s+(\d+)\s+(\d+)\s+(.+?)\s+(\d+)\s+\d+\s+(\d+)\s+\d+\s+(\d+)\s+\d+\s+(\d+)\s+\d+\s+\d+\s+\d+\s+\d+$/) {
for my $x ($stats{$3}) { # $3 -> the device name
$x->{major} = $1;
$x->{minor} = $2;
$x->{rdreq} = $4; # Field 1
$x->{rdbyt} = $5 * $bksz; # Field 3
$x->{wrtreq} = $6; # Field 5
$x->{wrtbyt} = $7 * $bksz; # Field 7
$x->{ttreq} += $x->{rdreq} + $x->{wrtreq};
$x->{ttbyt} += $x->{rdbyt} + $x->{wrtbyt};
}
}
# -----------------------------------------------------------------------------
# Field 1 -- # of reads issued
# This is the total number of reads issued to this partition.
# Field 2 -- # of sectors read
# This is the total number of sectors requested to be read from this
# partition.
# Field 3 -- # of writes issued
# This is the total number of writes issued to this partition.
# Field 4 -- # of sectors written
# This is the total number of sectors requested to be written to
# this partition.
# -----------------------------------------------------------------------------
# -- -- -- F1 F2 F3 F4
# $1 $2 $3 $4 $5 $6 $7
elsif ($line =~ /^\s+(\d+)\s+(\d+)\s+(.+?)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)$/) {
for my $x ($stats{$3}) { # $3 -> the device name
$x->{major} = $1;
$x->{minor} = $2;
$x->{rdreq} = $4; # Field 1
$x->{rdbyt} = $5 * $bksz; # Field 2
$x->{wrtreq} = $6; # Field 3
$x->{wrtbyt} = $7 * $bksz; # Field 4
$x->{ttreq} += $x->{rdreq} + $x->{wrtreq};
$x->{ttbyt} += $x->{rdbyt} + $x->{wrtbyt};
}
}
}
close($fh);
} elsif (open $fh, '<', $file_partitions) {
while (my $line = <$fh>) {
# -- -- -- -- F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11
# $1 $2 -- $3 $4 -- $5 -- $6 -- $7 -- -- -- --
next unless $line =~ /^\s+(\d+)\s+(\d+)\s+\d+\s+(.+?)\s+(\d+)\s+\d+\s+(\d+)\s+\d+\s+(\d+)\s+\d+\s+(\d+)\s+\d+\s+\d+\s+\d+\s+\d+$/;
for my $x ($stats{$3}) { # $3 -> the device name
$x->{major} = $1;
$x->{minor} = $2;
$x->{rdreq} = $4; # Field 1
$x->{rdbyt} = $5 * $bksz; # Field 3
$x->{wrtreq} = $6; # Field 5
$x->{wrtbyt} = $7 * $bksz; # Field 7
$x->{ttreq} += $x->{rdreq} + $x->{wrtreq};
$x->{ttbyt} += $x->{rdbyt} + $x->{wrtbyt};
}
}
close($fh);
} else {
croak "$class: unable to open $file_diskstats or $file_partitions ($!)";
}
if (!-e $file_diskstats || !scalar %stats) {
croak "$class: no diskstats found! your system seems not to be compiled with CONFIG_BLK_STATS=y";
}
return \%stats;
}
sub _deltas {
my $self = shift;
my $class = ref $self;
my $istat = $self->{init};
my $lstat = $self->{stats};
my $time = Time::HiRes::gettimeofday();
my $delta = sprintf('%.2f', $time - $self->{time});
$self->{time} = $time;
foreach my $dev (keys %{$lstat}) {
if (!exists $istat->{$dev}) {
delete $lstat->{$dev};
next;
}
my $idev = $istat->{$dev};
my $ldev = $lstat->{$dev};
while (my ($k, $v) = each %{$ldev}) {
next if $k =~ /^major\z|^minor\z/;
if (!defined $idev->{$k}) {
croak "$class: not defined key found '$k'";
}
if ($v !~ /^\d+\z/ || $ldev->{$k} !~ /^\d+\z/) {
croak "$class: invalid value for key '$k'";
}
if ($ldev->{$k} == $idev->{$k} || $idev->{$k} > $ldev->{$k}) {
$ldev->{$k} = sprintf('%.2f', 0);
} elsif ($delta > 0) {
$ldev->{$k} = sprintf('%.2f', ($ldev->{$k} - $idev->{$k}) / $delta);
} else {
$ldev->{$k} = sprintf('%.2f', $ldev->{$k} - $idev->{$k});
}
$idev->{$k} = $v;
}
}
}
1;
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