pmdaproc(1) — Linux manual page


PMDAPROC(1)              General Commands Manual             PMDAPROC(1)

NAME         top

       pmdaproc - process performance metrics domain agent (PMDA)

SYNOPSIS         top

       $PCP_PMDAS_DIR/proc/pmdaproc [-AL] [-d domain] [-l logfile] [-r
       cgroup] [-U username]

DESCRIPTION         top

       pmdaproc is a Performance Metrics Domain Agent (PMDA) which
       extracts performance metrics describing the state of the
       individual processes running on a Linux system.

       The proc PMDA exports metrics that measure the memory, processor
       and other resource use of each process, as well as summary
       information collated across all of the running processes.  The
       PMDA uses credentials passed from the PMAPI(3) monitoring tool
       identifying the user requesting the information, to ensure that
       only values the user is allowed to access are returned by the
       PMDA.  This involves the PMDA temporarily changing its effective
       user and group identifiers for the duration of requests for
       instances and values.  In other words, system calls to extract
       information are performed as the user originating the request and
       not as a privileged user.  The mechanisms available for transfer
       of user credentials are described further in the PCPIntro(1)

       A brief description of the pmdaproc command line options follows:

       -A   Disables use of the credentials provided by PMAPI client
            tools, and simply runs everything under the "root" account.
            Only enable this option if you understand the risks
            involved, and are sure that all remote accesses will be from
            benevolent users.  If enabled, unauthenticated remote PMAPI
            clients will be able to access potentially sensitive
            performance metric values which an unauthenticated PMAPI
            client usually would not be able to.  Refer to CVE-2012-3419
            for additional details.

       -L   Changes the per-process instance domain used by most
            pmdaproc metrics to include threads as well.

       -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
            proc.log is written in the current directory of pmcd(1) when
            pmdaproc 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   Restrict the set of processes exported in the per-process
            instance domain to only those processes that are contained
            by the specified cgroup resource container.  This option
            provides an optional finer granularity to the monitoring,
            and can also be used to reduce the resources consumed by
            pmdaproc during requests for instances and values.

       -U   User account under which to run the agent.  The default is
            the privileged "root" account, with seteuid (2) and setegid
            (2) switching for accessing most information.


       The pmdaproc Performance Metrics Domain Agent (PMDA) includes an
       additional set of per-process metrics with an instance domain of
       processes restricted to an "interesting" or "hot" set.  Unlike
       the stock metrics exported by the proc PMDA, which have an
       instance domain equal to the current processes, hot metrics have
       an instance domain which is a subset of this.  This hotproc
       instance domain is determined by a configurable predicate
       evaluated over some refresh interval.

       As well as the equivalent per-process proc metrics, hotproc
       provides a cpuburn metric which specifies the CPU utilization of
       the process over the refresh interval, total metrics which
       indicate how much of the available CPU time the "interesting"
       processes account for, predicate metrics which show the values of
       the reserved variables (see below) that are being used in the
       hotproc predicate, and control metrics for controlling the agent.


       The configuration file consists of one predicate used to
       determine if a process should be in the interesting set or not.

       An example configuration file may be found at

       This file with any modifications can be copied to
       $PCP_PMDAS_DIR/proc/hotproc.conf in order to configure the hot
       metrics. The pmstore(1) and pmStore(3) interfaces can be used as
       well (described below).

       The predicate is described using the language specified below.
       The symbols are based on those used by the C(1) and awk(1)

       Boolean Connectives
              && (and), || (or), !  (not), () (precedence overriding)

       Number comparators
              < , <= , > , >= , == , !=

       String comparators
              == , !=

       String/Pattern comparators
              ~ (string matches pattern) , !~ (string does not match

       Reserved variables
              uid (user id; type integer) uname (user name; type
              string), gid (group id; type integer) gname (group name;
              type string), fname (process file name; type string),
              psargs (process file name with args; type string), cpuburn
              (cpu utilization; type float), iodemand (I/O demand -
              Kbytes read/written per second; type float), ctxswitch
              (number of context switches per second; type float),
              syscalls (number of system calls per second; type float),
              virtualsize (virtual size in Kbytes; type float),
              residentsize (resident size in Kbytes; type float), iowait
              (blocked and raw io wait in secs/sec; type float),
              schedwait (time waiting in run queue in secs/sec; type

       Literal values
              1234 (positive integer), 0.35 (positive float), "foobar"
              (string; delimited by "), /[fF](o)+bar/ (pattern;
              delimited by /), true (boolean), false (boolean)

              #this is a comment (from # to the end of the line).

                cpuburn > 0.2 # cpu utilization of more than 20%
                cpuburn > 0.2 && uname == "root"
                cpuburn > 0.2 && (uname == "root" || uname == "hot")
                psargs ~ /pmda/ && cpuburn > 0.4

       The hotproc.predicate metrics may be used to see what the values
       of the reserved variables are that were used by the predicate at
       the last refresh.  They do not cover the reserved variables which
       are already exported elsewhere. A hotproc.predicate metric may
       not have a value if it is not referenced in the configuration


       The hot metrics can also be configured at runtime through the
       pmstore(1) interface (and, implicitly, the pmStore(3) API)

                pmstore hotproc.control.config 'fname == "mingetty"'
                pmstore hotproc.control.config 'uid == 0'

       To force the config file to be reloaded:
                pmstore hotproc.control.reload_config "1"

INSTALLATION         top

       The proc PMDA is installed and available by default.  If you want
       to undo the installation, do the following as root:

            # cd $PCP_PMDAS_DIR/proc
            # ./Remove

       If you want to establish access to the names, help text and
       values for the proc performance metrics once more, after removal,
       do the following as root:

            # cd $PCP_PMDAS_DIR/proc
            # ./Install

       pmdaproc 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 pmdaproc
              default help text file for the proc metrics
              installation script for the pmdaproc agent
              undo installation script for the pmdaproc agent
              default log file for error messages and other information
              from pmdaproc
              simple sample hotproc configuration
              default hotproc configuration file


       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), pmstore(1), seteuid(2), setegid(2),
       PMAPI(3), pcp.conf(5) and pcp.env(5).

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
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Performance Co-Pilot               PCP                       PMDAPROC(1)

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