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NAME    [Toc]    [Back]

     vmstat - report statistics about kernel activities

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

     vmstat reports certain kernel statistics kept about process,
virtual memory,
 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  of  fork(2),  rfork(2)  and
vfork(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 running kernel.

     -N system
             Extract  the name list from the specified system instead of the
             running kernel.

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

     -v      Print more verbose information.

     -z       When used with -i, also list devices which have not
yet generated
             an interrupt.

     By default, vmstat displays the following  information  just

     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

     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 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

               flt  page faults
               re   page reclaims (simulating reference bits)
               at   pages attached (found in free list)
               pi   pages paged in
               po   pages paged out
               fr   pages freed
               sr   pages scanned by clock algorithm

     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 two disk drives are configured in the system,
vmstat displays
 only the first two drives.  To force  vmstat
to display
               specific  drives,  their  names may be supplied on
the command

     traps     Trap/interrupt rate averages per second over  last
5 seconds.

               int  device  interrupts  per  interval  (including
clock interrupts)
               sys 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    [Toc]    [Back]

     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 often
  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.

SEE ALSO    [Toc]    [Back]

     fstat(1),  netstat(1),  nfsstat(1),  procmap(1), ps(1), systat(1),
     iostat(8), pstat(8)

     The sections starting with ``Interpreting system  activity''
in Installing
     and Operating 4.3BSD.

BUGS    [Toc]    [Back]

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

     This manual page lacks an incredible amount of detail.

OpenBSD      3.6                           June      6,      1993
[ Back ]
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