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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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NAME | SYNOPSIS | DESCRIPTION | INSTALLATION | FILES | UPGRADING | BUGS | PCP ENVIRONMENT | SEE ALSO | COLOPHON |
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PMDAPERFEVENT(1) General Commands Manual PMDAPERFEVENT(1)
pmdaperfevent - hardware performance counter performance metrics
domain agent (PMDA)
$PCP_PMDAS_DIR/perfevent/pmdaperfevent [-d domain] [-l logfile]
[-U username] [-i port] [-p] [-u socket] [-6]
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
PMDA.
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
sysctl(8).
A brief description of the pmdaperfevent 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
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 name)
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.
$PCP_PMCDCONF_PATH
command line options used to launch pmdaperfevent
$PCP_PMDAS_DIR/perfevent/perfevent.conf
default configuration file for the PMDA. See
perfevent.conf(5) for detailed information.
$PCP_PMDAS_DIR/perfevent/help
default help text file for the perfevent metrics
$PCP_PMDAS_DIR/perfevent/Install
installation script for the pmdaperfevent agent
$PCP_PMDAS_DIR/perfevent/Remove
undo installation script for the pmdaperfevent agent
$PCP_LOG_DIR/pmcd/perfevent.log
default log file for error messages and other information
from pmdaperfevent
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/perfevent-makerewrite.pl will generate a
config file that is suitable for use with pmlogrewrite(1) to
update the metric names in existing archives.
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 pcp.conf(5).
perfalloc(1), perfevent.conf(5), PCPIntro(1), pmcd(1),
pmlogrewrite(1), PMAPI(3), pcp.conf(5), pcp.env(5) and sysctl(8).
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 [email protected]. 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
[email protected]
Performance Co-Pilot PCP PMDAPERFEVENT(1)
Pages that refer to this page: pcp-atop(1), perfalloc(1), perfevent.conf(5)
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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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