pmdaoverhead - performance metrics domain agent (PMDA)
exporting resource consumption metrics for groups of processes
$PCP_PMDAS_DIR/overhead/pmdaoverhead [-C] [-c
config] [-d domain] [-l logfile]
[-R interval]
pmdaoverhead is a configurable Performance Metrics Domain
Agent (PMDA) for exporting resource consumption for groups of related
processes.
The pmdaoverhead command line options are:
- -C
- parse the configuration file(s) and exit after reporting any errors.
- -c
- configuration file(s), config may be either a file or a directory;
in the latter case all the files within config are assumed to be
configuration files for pmdaoverhead and they will all be
processed.
Each configuration file defines one or more ``groups'' of
processes of interest, using the syntax described in the ``CONFIGURATION''
section below.
By default all configuration files below the
$PCP_SYSCONF_DIR/overhead/conf.d/ directory are used.
- -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 overhead.log
is written in the current directory of pmcd(1) when
pmdaoverhead 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.
- -R
- The PMDA uses a separate thread to periodically scan all processes to
determine which processes are deemed ``interesting'' in each group, and
extracting resource consumption for those processes. The interval
(in seconds) determines how often this scanning and resource calculation
is done, the default is 60 (seconds).
Each configuration file defines one or more ``groups'' of
processes. The file format is simple and follows the following rules.
- 1.
- Lines beginning with a hash ``#'' are treated as comments. More generally,
except for the pattern: clause described below, all text between a
hash and the end of line is treated as a comment.
- 2.
- White space (spaces or tabs or newlines) are required to separate lexical
components. Spaces and tabs are otherwise ignored. Other than terminating
comments and the regex in a pattern: clause, newlines are
also ignored.
- 3.
- Each group is introduced by a group clause that has the form
group name { parameters }
where name is a unique name for the group across all groups in the
pmdaoverhead configuration files. As name becomes embedded
in the Performance Metrics Name Space (PMNS) if must follow the rules for
metric name components as described in PMNS(5), namely beginning
with an alphabetic character, followed by zero or more characters drawn
from the alphabetics, numerics and the underscore ``_'' character.
- 4.
- The parameters must include one id: clause and one
pattern: clause.
- 5.
- An id: clause has the form
id: ident
where ident is a unique identifier number for the group across all
groups in the pmdaoverhead configuration files. Valid values for
ident are in the range 0 to 4094 (inclusive).
- 6.
- A pattern: clause has the form
pattern: regex
where regex is an extended regular expression notation in the style
of egrep(1). The regex starts at the first non-whitespace
character after pattern: and extends to the next newline.
The processes that are considered to be members of the group are
those for which the command name, as reported by
$ pminfo -f proc.psinfo.cmd
is matched by regex plus all the
descendents of those processes. So for example the regex
^pmcd$ will match pmcd(1) and all the PMDA processes launched
by pmcd(1) and any of their children, etc.
If you want access to the names, help text and values for the
overhead performance metrics, do the following as root:
# cd $PCP_PMDAS_DIR/overhead
# ./Install
If you want to undo the installation, do the following as
root:
# cd $PCP_PMDAS_DIR/overhead
# ./Remove
pmdaoverhead is launched by pmcd and should never be
executed directly. The Install and Remove scripts notify pmcd when
the agent is installed or removed.
- $PCP_PMCDCONF_PATH
- command line options used to launch pmdaoverhead
- $PCP_PMDAS_DIR/overhead/Install
- installation script for the pmdaoverhead agent
- $PCP_PMDAS_DIR/overhead/Remove
- undo installation script for the pmdaoverhead agent
- $PCP_LOG_DIR/pmcd/overhead.log
- default log file for error messages and other information from
pmdaoverhead
- $PCP_SYSCONF_DIR/overhead/conf.d
- directory containing configuration files for the overhead metrics
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
configuration file, as described in pcp.conf(5).