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VMSTAT(1)              BSD Reference Manual             VMSTAT(1)


NAME
       vmstat - report virtual memory statistics

SYNOPSIS
       vmstat [ -fimst ] [ -c count ] [ -M core ] [ -N system ]
            [ -w wait ] [ disks ]

DESCRIPTION
       Vmstat  reports  certain kernel statistics kept about pro-
       cess, virtual memory, disk, trap and cpu activity.

       The options are as follows:

       -c     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  dis-
              play.   If  no  wait  interval  is  specified,  the
              default is 1 second.

       -f     Report on the number fork(2)  and  vfork(2)  system
              calls 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     Extract  values  associated with the name list from
              the  specified  core   instead   of   the   default
              ``/dev/kmem''.

       -N     Extract  the  name  list  from the specified system
              instead of the default ``/vmunix''.

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

       By default, vmstat displays the following information:





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VMSTAT(1)              BSD Reference Manual             VMSTAT(1)


       procs  Information about the numbers of processes in vari-
              ous 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 (reported in units  of  1024
              bytes) are considered active if they belong to pro-
              cesses 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  operations  per  second (this field is system
              dependent).  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 config-
              ured 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




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VMSTAT(1)              BSD Reference Manual             VMSTAT(1)


EXAMPLES
       The command ``vmstat -i 5'' will print what the system  is
       doing  every five seconds; this is a good choice of print-
       ing interval since this is how often some of  the  statis-
       tics  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
       /vmunix    default kernel namelist
       /dev/kmem  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  activ-
       ity'' in Installing and Operating 4.3BSD.

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
































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