MMV(3) User Contributed Perl Documentation MMV(3)NAME
PCP::MMV - Perl module for Memory Mapped Value instrumentation
SYNOPSIS
use PCP::MMV;
DESCRIPTION
The PCP::MMV Perl module contains the language bindings for building Perl programs instrumented with the Performance Co-Pilot Memory Mapped
Value infrastructure - an efficient data transport mechanism for making performance data from within a Perl program available as PCP
metrics using the MMV PMDA.
SEE ALSO mmv_stats_init(3), mmv_inc_value(3), mmv_lookup_value_desc(3), mmv(4) and pmda(3).
The PCP mailing list pcp@oss.sgi.com can be used for questions about this module.
Further details can be found at http://oss.sgi.com/projects/pcp
AUTHOR
Nathan Scott, <nathans@debian.org>
Copyright (C) 2009 by Aconex.
This library is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2 (see
the "COPYING" file in the PCP source tree for further details).
perl v5.16.3 2013-12-05 MMV(3)
Check Out this Related Man Page
PMDAMMV(1) General Commands Manual PMDAMMV(1)NAME
pmdammv - memory mapped values performance metrics domain agent (PMDA)
SYNOPSIS
$PCP_PMDAS_DIR/mmv/pmdammv [-d domain] [-l logfile] [-U username]
DESCRIPTION
pmdammv is a Performance Metrics Domain Agent (PMDA) which exports application level performance metrics using memory mapped files. It
offers an extremely low overhead instrumentation facility that is well-suited to long running, mission critical applications where it is
desirable to have performance metrics and availability information permanently enabled.
The mmv PMDA exports instrumentation that has been added to an application using the MMV APIs (refer to mmv_stats_init(3) and mmv(5) for
further details). These APIs can be called from several languages, including C, C++, Perl, Python and Java (via the separate ``Parfait''
class library).
A brief description of the pmdammv command line options follows:
-d It is absolutely crucial that the performance metrics domain number specified here is unique and consistent. That is, domain should
be different for every PMDA on the one host, and the same domain number should be used for the same PMDA on all hosts.
-l Location of the log file. By default, a log file named mmv.log is written in the current directory of pmcd(1) when pmdammv is
started, i.e. $PCP_LOG_DIR/pmcd. If the log file cannot be created or is not writable, output is written to the standard error
instead.
-U User account under which to run the agent. The default is the unprivileged "pcp" account in current versions of PCP, but in older
versions the superuser account ("root") was used by default.
INSTALLATION
If you want access to the names, help text and values for the mmv performance metrics, do the following as root:
# cd $PCP_PMDAS_DIR/mmv
# ./Install
Note that the default mechanism for sharing memory mapped values between instrumented applications and the mmv PMDA involves the creation
of a world-writeable $PCP_TMP_DIR/mmv directory with the sticky-bit set (similar to /tmp and /var/tmp, for example). This suffices to
allow any application, running under any user account, to communicate with the PMDA (which runs under the "pcp" account by default). This
may not be desirable for every environment, and one should consider the security implications of any directory setup like this (similar
classes of issues exist as those that affect the system temporary file directories).
The installation process will not overwrite any existing $PCP_TMP_DIR/mmv directory. Thus it is possible to implement an alternate permis-
sions strategy with no world-writable directory for sharing files - any directory readable by user or group "pcp" will suffice.
If you want to undo the installation, do the following as root:
# cd $PCP_PMDAS_DIR/mmv
# ./Remove
pmdammv 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.
FILES
$PCP_PMCDCONF_PATH
command line options used to launch pmdammv
$PCP_TMP_DIR/mmv
directory housing memory mapped value files
$PCP_PMDAS_DIR/mmv/help
default help text file for the mmv metrics
$PCP_PMDAS_DIR/mmv/Install
installation script for the pmdammv agent
$PCP_PMDAS_DIR/mmv/Remove
undo installation script for the pmdammv agent
$PCP_LOG_DIR/pmcd/mmv.log
default log file for error messages and other information from pmdammv
PCP ENVIRONMENT
Environment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP. On each installation, the
file /etc/pcp.conf contains the local values for these variables. The $PCP_CONF variable may be used to specify an alternative configura-
tion file, as described in pcp.conf(5).
SEE ALSO PCPIntro(1), pmcd(1), mmv_stats_init(3), mmv(5), pcp.conf(5) and pcp.env(5).
Performance Co-Pilot PCP PMDAMMV(1)