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 default is 1 second.

     -f      Report on the number fork(2), vfork(2), rfork(2) system calls as
             well as kernel thread creations since system startup, and the
             number of pages of virtual memory involved in each.

     -i      Report on the number of interrupts taken by each device since
             system 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
             default /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 num-
             ber 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 of-
     ten 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 2.9                      June 6, 1993                                2
