Ubuntu Manpage: pmdaperfevent - hardware performance counter performance metrics domain agent (PMDA)

NAME

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

SYNOPSIS

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

DESCRIPTION

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)

INSTALLATION

       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

       $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

UPGRADING

       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.

BUGS

       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.

PCP ENVIRONMENT

       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).