vmstat(8) - NetBSD Manual Pages

VMSTAT(8)                                               VMSTAT(8)



NAME

       vmstat - report virtual memory statistics


SYNOPSIS

       vmstat [ -fHilms ] [ -h histname ] [ -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 fork statistics.

       -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/mem''.

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

       -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.

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

       The following options only apply if vmstat was built  with
       support for UVM:

       -l     List the UVM histories being maintained by the ker-
              nel.

       -h     Dump the specified UVM history.

       -H     Dump all UVM histories.

       By default, vmstat displays the following information:




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VMSTAT(8)                                               VMSTAT(8)


       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  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  four  disk
              drives  are  configured  in the system, vmstat dis-
              plays only the first four drives.  To force  vmstat
              to display specific drives, their names may be sup-
              plied 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


EXAMPLES

       The  command ``vmstat -w 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



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VMSTAT(8)                                               VMSTAT(8)


       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.


FILES

       /netbsd   default kernel namelist
       /dev/mem  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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