pmdatrace(1) — Linux manual page


PMDATRACE(1)             General Commands Manual            PMDATRACE(1)

NAME         top

       pmdatrace - application-level transaction performance metrics
       domain agent

SYNOPSIS         top

       $PCP_PMDAS_DIR/trace/pmdatrace [-d domain] [-l logfile] [-A
       access] [-I port] [-M username] [-N buckets] [-T period] [-U

DESCRIPTION         top

       pmdatrace is a Performance Metrics Domain Agent (PMDA) which
       exports transaction performance metrics from application
       processes which use the pcp_trace library described in

       A brief description of the pmdatrace command line options

       -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

       -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

       -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

INSTALLATION         top

       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.

FILES         top

              command line options used to launch pmdatrace
              default help text file for the trace metrics
              example programs which use the pcp_trace library
              installation script for the pmdatrace agent
              undo installation script for pmdatrace
              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

SEE ALSO         top

       PCPIntro(1), pmcd(1), pmtrace(1), PMAPI(3) and pmdatrace(3).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨⟩ on 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-16.)  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

Performance Co-Pilot               PCP                      PMDATRACE(1)

Pages that refer to this page: pmtrace(1)__pmaf(3)pmdatrace(3)