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



NAME
       vmstat - report virtual memory statistics

SYNOPSIS
       vmstat [ -cfisS ] [ interval [ count ] ]

DESCRIPTION
       vmstat  delves  into the system and normally reports certain statistics
       kept about process, virtual memory, disk, trap and CPU activity.

       Without options, vmstat displays a one-line summary of the virtual mem-
       ory  activity  since the system has been booted.  If interval is speci-
       fied, vmstat summarizes activity over the last interval seconds.  If  a
       count is given, the statistics are repeated count times.

       For  example, the following command displays a summary of what the sys-
       tem 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.
              example% vmstat 5
              procs     memory                       page      faults
              r b w   avm  fre  re at  pi  po  fr  de  sr x0 x1 x2 x3  in   sy  cs  us  sy  id
              2 0 0   918  286   0  0   0   0   0   0    0  1  0   0   0    4  12    5   3   5  91
              1 0 0   846  254   0  0   0   0   0   0    0  6  0   1   0   42 153  31  7  40  54
              1 0 0   840  268   0  0   0   0   0   0    0  5  0   0   0   27 103  25  8  26  66
              1 0 0   620  312   0  0   0   0   0   0    0  6  0   0   0   26  76  25  6  27  67
              CTRL-C
              example%

       The fields of vmstat's display are:

       procs   Report the number of processes in each of the  three  following
               states:
               r       in run queue
               b       blocked for resources (i/o, paging, etc.)
               w       runnable or short sleeper (< 20 secs) but swapped

       memory  Report  on usage of virtual and real memory.  Virtual memory is
               considered active if it belongs to processes which are  running
               or have run in the last 20 seconds.
               avm     number of active virtual Kbytes
               fre     size of the free list in Kbytes

       page    Report  information about page faults and paging activity.  The
               information on each of the  following  activities  is  averaged
               each five seconds, and given in units per second.
               re      page  reclaims  --  but  see the -S option for how this
                       field is modified.
               at      number of attaches -- but see the  -S  option  for  how
                       this field is modified.
               pi      kilobytes per second paged in
               po      kilobytes per second paged out
               fr      kilobytes freed per second
               de      anticipated short term memory shortfall in Kbytes
               sr      pages scanned by clock algorithm, per-second

       disk    Report number of disk operations per second (this field is sys-
               tem dependent).  For Sun systems, four slots are available  for
               up  to  four drives: ``x0'' (or ``s0'' for SCSI disks), ``x1'',
               ``x2'', and ``x3''.

       faults  Report trap/interrupt rate averages per second over last 5 sec-
               onds.
               in      (non clock) device interrupts per second
               sy      system calls per second
               cs      CPU context switch rate (switches/sec)

       cpu     Give a breakdown of percentage usage of CPU time.
               us      user time for normal and low priority processes
               sy      system time
               id      CPU idle

OPTIONS
       -c     Report  cache flushing statistics.  By default, report the total
              number of each kind of cache flushed since boot time.  The types
              are: user, context, region, segment, page, and partial-page.

       -f     Report  on  the  number of forks and vforks since system startup
              and the number of pages of virtual memory involved in each  kind
              of fork.

       -i     Report the number of interrupts per device.  Autovectored inter-
              rupts (including the clock) are listed first.

       -s     Display the contents of the sum structure, giving the total num-
              ber  of  several  kinds  of  paging-related  events  which  have
              occurred since boot.

       -S     Report on swapping rather than  paging  activity.   This  option
              will  change  two fields in vmstat's ``paging'' display:  rather
              than the ``re'' and ``at'' fields,  vmstat  will  report  ``si''
              (swap-ins), and ``so'' (swap-outs).

FILES
       /dev/kmem
       /vmunix

BUGS
       If  more than one autovectored device has the same name, interrupts are
       counted for all like-named devices regardless  of  unit  number.   Such
       devices are listed with a unit number of `?'.



                               7 September 1988                      VMSTAT(8)