vmstat

NAME

       vmstat - Report virtual memory statistics

SYNOPSIS

       vmstat [-n] [delay [ count]]
       vmstat[-V]

DESCRIPTION

       vmstat  reports  information about processes, memory, pag-
       ing, block IO, traps, and cpu activity.

       The first report produced gives averages  since  the  last
       reboot.  Additional reports give information on a sampling
       period of length delay.  The process  and  memory  reports
       are instantaneous in either case.


   Options
       The -n switch  causes the header to be displayed only once
       rather than periodically.

       delay is the delay between  updates  in  seconds.   If  no
       delay  is  specified,  only one report is printed with the
       average values since boot.

       count is the number of updates.  If no count is  specified
       and delay is defined, count defaults to infinity.

       The -V switch results in displaying version information.

FIELD DESCRIPTIONS

   Procs
       r: The number of processes waiting for run time.
       b: The number of processes in uninterruptable sleep.
       w: The number of processes swapped out but otherwise runnable.  This
          field is calculated, but Linux never desperation swaps.


   Memory
       swpd: the amount of virtual memory used (kB).
       free: the amount of idle memory (kB).
       buff: the amount of memory used as buffers (kB).


   Swap
       si: Amount of memory swapped in from disk (kB/s).
       so: Amount of memory swapped to disk (kB/s).


   IO
       bi: Blocks sent to a block device (blocks/s).
       bo: Blocks received from a block device (blocks/s).

   System
       in: The number of interrupts per second, including the clock.
       cs: The number of context switches per second.

   CPU
       These are percentages of total CPU time.
       us: user time
       sy: system time
       id: idle time

NOTES

       vmstat does not require special permissions.

       These reports are intended to help identify system bottle-
       necks.  Linux vmstat does not count itself  as  a  running
       process.

       All  linux  blocks  are  currently  1k,  except for CD-ROM
       blocks which are 2k.

FILES

       /proc/meminfo
       /proc/stat
       /proc/*/stat

SEE ALSO

       ps(1), top(1), free(1)

BUGS

       Does not tabulate the block io per  device  or  count  the
       number of system calls.

AUTHOR

       Written by Henry Ware <al172@yfn.ysu.edu>.