VMSTAT(1)               NetBSD General Commands Manual               VMSTAT(1)

NAME
     vmstat -- report virtual memory statistics

SYNOPSIS
     vmstat [-CefHiLlmstUvW] [-c count] [-h hashname] [-M core] [-N system]
            [-u histname] [-w wait] [disks]

DESCRIPTION
     vmstat reports certain kernel statistics kept about process, virtual mem-
     ory, disk, trap, and CPU activity.

     The options are as follows:

     -C           Report on kernel memory caches.  Combine with the -m option
                  to see information about memory pools that back the caches.

     -c count     Repeat the display count times.  The first display is for
                  the time since a reboot and each subsequent report is for
                  the time period since the last display.  If no wait interval
                  is specified, the default is 1 second.

     -e           Report the values of system event counters.

     -f           Report fork statistics.

     -H           Report all hash table statistics.

     -h hashname  Report hash table statistics for hashname.

     -i           Report the values of system interrupt counters.

     -L           List all the hashes supported for -h and -H.

     -l           List the UVM histories being maintained by the kernel.

     -M core      Extract values associated with the name list from the speci-
                  fied core instead of the default /dev/mem.

     -m           Report on the usage of kernel dynamic memory listed first by
                  size of allocation and then by type of usage, followed by a
                  list of the kernel memory pools and their usage.

     -N system    Extract the name list from the specified system instead of
                  the default /netbsd.

     -s           Display the contents of the uvmexp structure.  This contains
                  various paging event and memory status counters.

     -t           Display the contents of the vmtotal structure.  This
                  includes information about processes and virtual memory.

                  The process part shows the number of processes in the fol-
                  lowing states:

                  ru   on the run queue
                  dw   in disk I/O wait
                  pw   waiting for paging
                  sl   sleeping

                  The virtual memory section shows:

                  total-v   Total virtual memory
                  active-v  Active virtual memory in use
                  active-r  Active real memory in use
                  vm-sh     Shared virtual memory
                  avm-sh    Active shared virtual memory
                  rm-sh     Shared real memory
                  arm-sh    Active shared real memory
                  free      Free memory

                  All memory values are shown in number of pages.

     -U           Dump all UVM histories.

     -u histname  Dump the specified UVM history.

     -v           Print more verbose information.  When used with the -i, -e,
                  or -m options prints out all counters, not just those with
                  non-zero values.

     -W           Print more verbose information about kernel memory pools.

     -w wait      Pause wait seconds between each display.  If no repeat count
                  is specified, the default is infinity.

     By default, vmstat displays the following information:

     procs   Information about the numbers of processes in various states.

             r     in run queue
             b     blocked for resources (i/o, paging, etc.)

     memory  Information about the usage of virtual and real memory.  Virtual
             pages (reported in units of 1024 bytes) are considered active if
             they belong to processes which are running or have run in the
             last 20 seconds.

             avm   active virtual pages
             fre   size of the free list

     page    Information about page faults and paging activity.  These are
             averaged every five seconds, and given in units per second.

             flt   total page faults
             re    page reclaims (simulating reference bits)
             pi    pages paged in
             po    pages paged out
             fr    pages freed per second
             sr    pages scanned by clock algorithm, per-second

     disks   Disk transfers per second.  Typically paging will be split across
             the available drives.  The header of the field is the first char-
             acter of the disk name and the unit number.  If more than four
             disk drives are configured in the system, vmstat displays only
             the first four drives.  To force vmstat to display specific
             drives, their names may be supplied on the command line.

     faults  Trap/interrupt rate averages per second over last 5 seconds.

             in    device interrupts per interval (including clock interrupts)
             sy    system calls per interval
             cs    CPU context switch rate (switches/interval)

     cpu     Breakdown of percentage usage of CPU time.

             us    user time for normal and low priority processes
             sy    system time
             id    CPU idle

FILES
     /netbsd     default kernel namelist
     /dev/mem    default memory file

EXAMPLES
     The command ``vmstat -w 5'' will print what the system is doing every
     five seconds; this is a good choice of printing interval since this is
     how often some of the statistics are sampled in the system.  Others vary
     every second and running the output for a while will make it apparent
     which are recomputed every second.

SEE ALSO
     fstat(1), netstat(1), nfsstat(1), ps(1), systat(1), iostat(8), pstat(8)

     The sections starting with ``Interpreting system activity'' in Installing
     and Operating 4.3BSD.

BUGS
     The -c and -w options are only available with the default output.

     The -l, -U, and -u options are useful only if the system was compiled
     with support for UVM history.

NetBSD 6.1.5                   October 22, 2009                   NetBSD 6.1.5

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©1996-2014 Modified for NetBSD by Kimmo Suominen