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).