VMSTAT(1-BSD)       RISC/os Reference Manual        VMSTAT(1-BSD)



NAME
     vmstat - report virtual memory statistics

SYNOPSIS
     vmstat [ -fsim ] [ 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 since system startup.  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
     given a -m argument, it instead reports on the usage of ker-
     nel dynamic memory listed first by size of allocation and
     then by type of usage.

     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.  These values are expressed in units of 1024 bytes.

          avm  active virtual memory
          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.





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VMSTAT(1-BSD)       RISC/os Reference Manual        VMSTAT(1-BSD)



          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

     ip/is/sd/vj: 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.  To force vmstat to
     display specific drives, their names may be supplied on the
     command line.

FILES
     /dev/kmem
     /unix

SEE ALSO
     systat(1-BSD), iostat(1-BSD).


















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