NAME

       pmdaaix, pmdadarwin, pmdafreebsd, pmdalinux, pmdanetbsd, pmdaproc, pmdasolaris, pmdawindows, kernel PMDAs
       - operating system kernel performance metrics domain agents

SYNOPSIS

       $PCP_PMDAS_DIR/aix/pmdaaix [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/darwin/pmdadarwin [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/freebsd/pmdafreebsd [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/linux/pmdalinux [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/netbsd/pmdanetbsd [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/solaris/pmdasolaris [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/windows/pmdawindows [-d domain] [-l logfile] [-U username]

DESCRIPTION

       Each  supported  platform has a kernel Performance Metrics Domain Agent (PMDA) which extracts performance
       metrics from the kernel of that platfrom.  A variety of platform-specific metrics are available, with  an
       equally  varied  set of access mechanisms - typically this involves special system calls, or reading from
       files in kernel virtual filesystems such as the Linux sysfs and procfs filesystems.

       The platform kernel PMDA is one of the most critical components of the PCP installation, and must  be  as
       efficient  and reliable as possible.  In all installations the default kernel PMDA will be installed as a
       shared library and thus executes directly within the pmcd(1) process.  This  slightly  reduces  overheads
       associated  with  querying  the  metadata and values associated with these metrics (no message passing is
       required).

       Unlike many other PMDAs, the kernel PMDA exports a number of metric namespace subtrees, such  as  kernel,
       network, swap, mem, ipc, filesys, nfs, disk and hinv (hardware inventory).

       Despite usually running as shared libraries, most installations also include a stand-alone executable for
       the kernel PMDA.  This is to aid profiling and debugging activities, with dbpmda(1) for example.  In this
       case (but not for shared libraries), the following command line options are available:

       -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 [platform].log is  written  in  the  current
            directory  of  pmcd(1)  when  pmda[platform]  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 unprivileged "pcp" account in current
            versions of PCP, but in older versions the superuser account ("root") was used by default.

INSTALLATION

       Access to the names, help text and values for the kernel performance metrics is available  by  default  -
       unlike most other agents, no action is required to enable them and they should not be removed.

FILES

       $PCP_PMDAS_DIR/[platform]/help
                 default help text file for the the kernel metrics
       $PCP_LOG_DIR/pmcd/pmcd.log
                 default log file for error messages and other information from the kernel PMDA.

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).

SEE ALSO

       PCPIntro(1), dbpmda(1) pmcd(1), pcp.conf(5) and pcp.env(5).

Performance Co-Pilot                                   PCP                                       KERNEL PMDAS(1)