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#
# Copyright (c) 2012 Red Hat.
# Copyright (c) 2008 Aconex. All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
use strict;
use warnings;
use PCP::PMDA;
use vars qw( $pmda $id );
my $probe_indom = 0;
my $probe_script = pmda_config('PCP_PMDAS_DIR') . '/systemtap/probes.stp';
my $probe_command = "/usr/bin/stap -m pmdasystemtap $probe_script";
my @probe_instances = ( 0 => 'sync', 1 => 'readdir' );
my ( $sync_count, $sync_pid, $sync_cmd ) = ( 0, 0, "(none)" );
my ( $readdir_count, $readdir_pid, $readdir_cmd ) = ( 0, 0, "(none)" );
sub systemtap_input_callback
{
( $id, $_ ) = @_;
# $pmda->log($_);
if (/^readdir: \((\d+)\) (.*)$/) {
( $readdir_pid, $readdir_cmd ) = ( $1, $2 );
$readdir_count++;
}
elsif (/^sync: \((\d+)\) (.*)$/) {
( $sync_pid, $sync_cmd ) = ( $1, $2 );
$sync_count++;
}
}
sub systemtap_fetch_callback
{
my ($cluster, $item, $inst) = @_;
if ($inst < 0 || $inst > 1) { return (PM_ERR_INST, 0); }
if ($cluster == 0) {
if ($item == 0) {
if ($inst == 0) { return ($sync_count, 1); }
else { return ($readdir_count, 1); }
}
elsif ($item == 1) {
if ($inst == 0) { return ($sync_pid, 1); }
else { return ($readdir_pid, 1); }
}
elsif ($item == 2) {
if ($inst == 0) { return ($sync_cmd, 1); }
else { return ($readdir_cmd, 1); }
}
}
return (PM_ERR_PMID, 0);
}
$pmda = PCP::PMDA->new('systemtap', 88);
$pmda->add_metric(pmda_pmid(0,0), PM_TYPE_U32, $probe_indom,
PM_SEM_COUNTER, pmda_units(0,0,1,0,0,PM_COUNT_ONE),
'systemtap.probes.count',
'Number of times the probe has been observed', '');
$pmda->add_metric(pmda_pmid(0,1), PM_TYPE_32, $probe_indom,
PM_SEM_INSTANT, pmda_units(0,0,0,0,0,0),
'systemtap.probes.pid',
'The PID of the last process to pass the probe point', '');
$pmda->add_metric(pmda_pmid(0,2), PM_TYPE_STRING, $probe_indom,
PM_SEM_INSTANT, pmda_units(0,0,0,0,0,0),
'systemtap.probes.cmd',
'The name of the last process to pass the probe point', '');
$pmda->add_indom($probe_indom, \@probe_instances,
'Instance domain exporting each SystemTap probe', '');
$pmda->set_fetch_callback(\&systemtap_fetch_callback);
$pmda->add_pipe($probe_command, \&systemtap_input_callback, 0);
$pmda->set_user('pcp');
$pmda->run;
=pod
=head1 NAME
pmdasystemtap - Systemtap performance metrics domain agent (PMDA)
=head1 DESCRIPTION
B<pmdasystemtap> is a Performance Metrics Domain Agent (PMDA) which exports
metric values from the Linux Systemtap dynamic tracing toolkit.
This implementation uses the stap(1) tool, which is a front-end to
the Systemtap toolkit.
=head1 INSTALLATION
In order to access performance data exported by Systemtap from
with PCP, it is necessary to perform two configuration steps:
=over
=item 1.
Configure Systemtap probes, and verify them with stap(1).
These should be produced in a format that is easily parsed,
and then stored in the $PCP_PMDAS_DIR/systemtap/probes.stp
file.
=item 2.
Configure B<pmdasystemtap> to extract the values from the text
produced by stap. Two example probes are implemented in the
default systemtap PMDA script - readdir and sync traces (see
$PCP_PMDAS_DIR/systemtap/pmdasystemtap.pl for details).
=back
# cd $PCP_PMDAS_DIR/systemtap
# [ edit probes.stp, test /usr/bin/stap probes.stp ]
# [ edit pmdasystemtap.pl ]
Once this is setup, you can access the names and values for the
systemtap performance metrics by doing the following as root:
# cd $PCP_PMDAS_DIR/systemtap
# ./Install
If you want to undo the installation, do the following as root:
# cd $PCP_PMDAS_DIR/systemtap
# ./Remove
B<pmdasystemtap> is launched by pmcd(1) and should never be executed
directly. The Install and Remove scripts notify pmcd(1) when
the agent is installed or removed.
=head1 FILES
=over
=item $PCP_PMDAS_DIR/systemtap/probes.stp
probe configuration file for stap(1), run by B<pmdasystemtap>
=item $PCP_PMDAS_DIR/systemtap/Install
installation script for the B<pmdasystemtap> agent
=item $PCP_PMDAS_DIR/systemtap/Remove
undo installation script for the B<pmdasystemtap> agent
=item $PCP_LOG_DIR/pmcd/systemtap.log
default log file for error messages from B<pmdasystemtap>
=back
=head1 SEE ALSO
pmcd(1) and stap(1).
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