2.11BSD#431 - /usr/man/cat1/vmstat.0

VMSTAT(1)	    UNIX Programmer's Manual		VMSTAT(1)


NAME
     vmstat - report virtual memory statistics

SYNOPSIS
     vmstat [ -fsi ] [ drives ] [ interval [ count ] ]

DESCRIPTION
     Vmstat delves into the system and normally reports certain
     statistics kept about process, virtual memory, disk, trap
     and cpu activity.	If given a -f argument, it instead
     reports on the number of forks and vforks since system
     startup and the number of pages of virtual memory involved
     in each kind of fork.  If given a -s argument, it instead
     prints the contents of the sum structure, giving the total
     number of several kinds of paging related events which have
     occurred since boot.  If given a -i argument, it instead
     reports on the number of interrupts taken by each device
     since system startup.

     If none of these options are given, vmstat will report in
     the first line a summary of the virtual memory activity
     since the system has been booted.	If interval is specified,
     then successive lines are summaries over the last interval
     seconds.  ``vmstat 5'' will print what the system is doing
     every five seconds; this is a good choice of printing inter-
     val since this is how often some of the statistics are sam-
     pled in the system; others vary every second, running the
     output for a while will make it apparent which are recom-
     puted every second.  If a count is given, the statistics are
     repeated count times.  The format fields are:

     Procs: information about 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.  Virtual pages are considered active if they belong
     to processes which are running or have run in the last 20
     seconds.  A ``page'' here is 1024 bytes.

     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)


Printed 11/26/99	 March 15, 1986                         1


VMSTAT(1)	    UNIX Programmer's Manual		VMSTAT(1)


     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

     up/hp/rk/ra: Disk operations per second (this field is sys-
     tem dependent).  Typically paging will be split across
     several of the available drives.  The number under each of
     these is the unit number.

     Faults: trap/interrupt rate averages per second over last 5
     seconds.

     in   (non clock) device interrupts per second
     sy   system calls per second
     cs   cpu context switch rate (switches/sec)

     Cpu: breakdown of percentage usage of CPU time

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

     If more than 4 disk drives are configured in the system,
     vmstat displays only the first 4 drives, with priority given
     to Massbus disk drives (i.e. if both Unibus and Massbus
     drives are present and the total number of drives exceeds 4,
     then some number of Unibus drives will not be displayed in
     favor of the Massbus drives).  To force vmstat to display
     specific drives, their names may be supplied on the command
     line.

FILES
     /dev/kmem, /vmunix

SEE ALSO
     systat(1), iostat(1)

     The sections starting with ``Interpreting system activity''
     in Installing and Operating 4.2bsd.


Printed 11/26/99	 March 15, 1986                         2