VMSTAT(8)               OpenBSD System Manager's Manual              VMSTAT(8)

NAME
     vmstat - report virtual memory statistics



SYNOPSIS
     vmstat [-fimst]
     vmstat [-c count] [-M core] [-N system] [-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 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 de-
           fault is 1 second.

     -f    Report on the number fork(2),  vfork(2),  and rfork(2) system calls
           since system startup, and the number of pages of virtual memory in-
           volved in each.

     -i    Report on the number of interrupts taken by each device since sys-
           tem startup.

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

     -N system
           Extract the name list from the specified system instead of the de-
           fault /bsd.

     -m    Report on the usage of kernel dynamic memory listed first by size
           of allocation and then by type of usage.

     -s    Display the contents of the sum structure, giving the total number
           of several kinds of paging related events which have occurred since
           system startup.

     -t    Report on the number of page in and page reclaims since system
           startup, and the amount of time required by each.

     -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 just once:

     procs     Information about the numbers of processes in various states.

               r in run queue
               b blocked for resources (i/o, paging, etc.)
               w runnable or short sleeper (< 20 secs) but swapped

     memory    Information about the usage of virtual and real memory.  Virtu-
               al pages (reported in units of 1024 bytes) are considered ac-
               tive 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 each five seconds, and given in units per second.

               re page reclaims (simulating reference bits)
               at pages attached (found in free list)
               pi pages paged in
               po pages paged out
               fr pages freed per second
               de anticipated short term memory shortfall
               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 character of the disk name and the unit number.  If more
               than four disk drives are configured in the system, vmstat dis-
               plays 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

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.

FILES
     /bsd           Default kernel namelist
     /dev/mem       Default memory file

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.

     This manual page lacks an incredible amount of detail.

OpenBSD 2.3                      June 6, 1993                                2