pmdaperfevent(1) — Linux manual page


PMDAPERFEVENT(1)         General Commands Manual        PMDAPERFEVENT(1)

NAME         top

       pmdaperfevent - hardware performance counter performance metrics
       domain agent (PMDA)

SYNOPSIS         top

       $PCP_PMDAS_DIR/perfevent/pmdaperfevent [-d domain] [-l logfile]
       [-U username] [-i port] [-p] [-u socket] [-6]

DESCRIPTION         top

       pmdaperfevent is a Performance Metrics Domain Agent (PMDA) that
       configures and reads the hardware performance counters using the
       Linux kernel perf_event API.

       The perfevent PMDA exports metrics for hardware performance
       counters that are configurable from the Linux kernel perf_event
       API.  The PMDA uses the libpfm4 library to access the hardware
       performance counters so any counters that are supported in
       libpfm4 should be available.  Also included is the ability to
       read the Intel RAPL counters via direct MSR access.  The PMDA
       supports automatically loading different counters for each
       hardware architecture.  A single configuration file is used to
       specify the desired counters for each hardware performance
       monitoring unit (PMU).  The configuration file allows different
       counters to be programmed on different CPUs and supports round-
       robin assignment of uncore counters needed for some AMD chips.

       The PMDA also counts for events exposed in the kernel via
       /sys/bus/event_source/devices directory. The PMU device name and
       the event name must be mentioned in the configuration file.
       Otherwise, the metric won't be available to monitor through this

       The PMDA configures the counters to count events in both user and
       kernel mode.  This means that the hardware counters are
       unavailable to use by normal unprivileged user applications when
       they are in use by the PMDA.  The PMDA provides a mechanism to
       temporarily disable the system-wide counters in order to allow
       normal users to be able to use the counters if they wish.  See
       perfalloc(1) for details.

       Note that pmdaperfevent is affected by the value of the
       kernel.perf_event_paranoid setting, which can be adjusted by

       A brief description of the pmdaperfevent 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
            perfevent.log is written in the current directory of pmcd(1)
            when pmdaperfevent 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.

       -U   User account under which to run the agent.  The default is
            the privileged "root" account.

       -i   listen on given port number for connection from pmcd(1)

       -p   communicate with pmcd(1) via stdin/stdout

       -u   expect pmcd(1) to connect on given unix domain socket

       -6   expect pmcd(1) to connect on given ipv6 port (number or

INSTALLATION         top

       The perfevent PMDA is not activated by default To install the
       PMDA, do the following as root:

            # cd $PCP_PMDAS_DIR/perfevent
            # ./Install

       If you want to undo the installation, do the following as root:

            # cd $PCP_PMDAS_DIR/perfevent
            # ./Remove

       pmdaperfevent 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 pmdaperfevent
              default configuration file for the PMDA.  See
              perfevent.conf(5) for detailed information.
              default help text file for the perfevent metrics
              installation script for the pmdaperfevent agent
              undo installation script for the pmdaperfevent agent
              default log file for error messages and other information
              from pmdaperfevent

UPGRADING         top

       Some metric names have changed starting in version 3.10.8 to
       better conform to PMNS conventions.  pmlogrewrite(1) can be used
       to update old archives.  A helper utility,
       $PCP_PMDAS_DIR/perfevent/ will generate a
       config file that is suitable for use with pmlogrewrite(1) to
       update the metric names in existing archives.

BUGS         top

       Each event is placed in its own group and there is no way to
       group related events together so they are guaranteed to be
       simultaneously active.  A workaround for this is to ensure that
       the number of configured events is less than or equal to the
       number of available hardware counters.  This means that the
       events will not be time-multiplexed by the kernel and will be
       simultaneously active.


       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

       perfalloc(1), perfevent.conf(5), PCPIntro(1), pmcd(1),
       pmlogrewrite(1), PMAPI(3), pcp.conf(5), pcp.env(5) and sysctl(8).

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                  PMDAPERFEVENT(1)

Pages that refer to this page: pcp-atop(1)perfalloc(1)perfevent.conf(5)