NAME

       pmdazswap - zswap (compressed swap) PMDA

DESCRIPTION

       pmdazswap  is  a Performance Metrics Domain Agent (PMDA) which exports metric values about
       compressed swap operation, as tracked by the zswap Linux kernel module.

       Zswap is a lightweight compressed cache for swap pages.  It takes pages that  are  in  the
       process  of  being  swapped out and attempts to compress them into a dynamically allocated
       RAM-based memory pool.  Zswap trades CPU cycles for potentially reduced  swap  I/O.   This
       tradeoff  can  also result in a performance improvement if reads from the compressed cache
       are faster than reads from a swap device.

       This PMDA exports metrics about pool size, number of pages stored,  and  various  counters
       for the reasons pages are rejected.

INSTALLATION

       Install the zswap PMDA by using the Install script as root:

             # cd $PCP_PMDAS_DIR/zswap
             # ./Install

       To uninstall, do the following as root:

             # cd $PCP_PMDAS_DIR/zswap
             # ./Remove

       pmdazswap  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_PMDAS_DIR/zswap/Install
           installation script for the pmdazswap agent

       $PCP_PMDAS_DIR/zswap/Remove
           undo installation script for the pmdazswap agent

       $PCP_LOG_DIR/pmcd/zswap.log
           default log file for error messages from pmdazswap

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

       pmcd(1) and PCPIntro(1).