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NAME | SYNOPSIS | DESCRIPTION | INSTALLATION | FILES | PCP ENVIRONMENT | DEBUGGING OPTIONS | SEE ALSO | COLOPHON |
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PMDATRACE(1) General Commands Manual PMDATRACE(1)
pmdatrace - application-level transaction performance metrics
domain agent
$PCP_PMDAS_DIR/trace/pmdatrace [-D debug] [-d domain] [-l logfile]
[-A access] [-I port] [-M username] [-N buckets] [-T period] [-U
units]
pmdatrace is a Performance Metrics Domain Agent (PMDA) which
exports transaction performance metrics from application processes
which use the pcp_trace library described in pmdatrace(3).
A brief description of the pmdatrace 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
trace.log is written in the current directory of pmcd(1) when
pmdatrace 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.
-A Host-based access control for pmdatrace. access must be
either an allow or deny specification, using either
allow:hostspec:maxconns or disallow:hostspec, where `allow'
and `disallow' are keywords, `hostspec' is a host
specification conforming to the format used by both pmcd(1)
and pmlogger(1), and `maxconns' is the maximum number of
connections allowed from a given `hostspec'. Using a maximum
connections of zero specifies an unlimited number of
connections for the accompanying `hostspec'.
-I Communicate with pcp_trace clients via the given Internet
port. This can alternatively be specified by setting
$PCP_TRACE_PORT in the environment to some valid port number
(use of the -I option overrides this). The default port
number is 4323.
-T period defines the aggregation period used to compute the
recent averages and extrema. Specified as a time interval
using the syntax described in PCPIntro(1) for the common -t
PCP argument, e.g. 30 seconds or 1 min. The default is 60
seconds.
-M 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.
-N Internally, the aggregation period is divided into bucket
divisions, and the rolling average is recomputed every
period/bucket seconds. For example, the defaults correspond
to -T 60 and -N 12, which means the average is recomputed
every five seconds for a period covering the prior 60
seconds.
-U This option allows the dimension and scale associated with
the observation value metric to be configured. units is a
comma-separated string of six integer values, which are the
space dimension, time dimension, count dimension, space
scale, time scale, and count scale, respectively. The
default dimension and scale is ``none'', which is equivalent
to presenting ``0,0,0,0,0,0'' as the argument to -U. The
units associated with a metric are most easily viewed using
the -d (metric description) option to pminfo(1). The Install
script described below steps through this option quite
explicitly, so it is recommended that the Install script be
used for building up the units specification.
Essentially, the exported metrics provide statistics on the time
for completion of each transaction, and an average count of
transactions completed and watch points passed over a given time
period.
In order for a host to export the names, help text and values for
the Trace performance metrics, do the following as root:
# cd $PCP_PMDAS_DIR/trace
# ./Install
If you want to undo the installation, do the following as root:
# cd $PCP_PMDAS_DIR/trace
# ./Remove
pmdatrace 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.
$PCP_PMCDCONF_PATH
command line options used to launch pmdatrace
$PCP_PMDAS_DIR/trace/help
default help text file for the trace metrics
$PCP_DEMOS_DIR/trace/*
example programs which use the pcp_trace library
$PCP_PMDAS_DIR/trace/Install
installation script for the pmdatrace agent
$PCP_PMDAS_DIR/trace/Remove
undo installation script for pmdatrace
$PCP_LOG_DIR/pmcd/trace.log
default log file for error messages and other information
from pmdatrace
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).
The -D or --debug option enables the output of additional
diagnostics on stderr to help triage problems, although the
information is sometimes cryptic and primarily intended to provide
guidance for developers rather end-users. debug is a comma
separated list of debugging options; use pmdbg(1) with the -l
option to obtain a list of the available debugging options and
their meaning.
Debugging options specific to pmdatrace are as follows:
┌────────┬───────────────────────────────────────────────────────┐
│ Option │ Description │
├────────┼───────────────────────────────────────────────────────┤
│ appl0 │ authentication parsing, client changes, IPC, metric │
│ │ data and metadata refreshes │
├────────┼───────────────────────────────────────────────────────┤
│ appl1 │ raw data for rate metrics │
└────────┴───────────────────────────────────────────────────────┘
PCPIntro(1), pmcd(1), pmtrace(1), PMAPI(3) and pmdatrace(3).
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at
⟨http://www.pcp.io/⟩. If you have a bug report for this manual
page, send it to pcp@groups.io. This page was obtained from the
project's upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2025-08-11.
(At that time, the date of the most recent commit that was found
in the repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMDATRACE(1)
Pages that refer to this page: pmtrace(1), __pmaf(3), pmdatrace(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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