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) page.

       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

       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) languages.

       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 float).

       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 predicate.


       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 pcp.conf(5).

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
       2020-08-13.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-11.)  If you discover any
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       (which is not part of the original manual page), send a mail to

Performance Co-Pilot                 PCP                         PMDAPROC(1)

Pages that refer to this page: pcp-atop(1)pcp-atopsar(1)pmda(3)PMDA(3)