vmstat

VMSTAT(8)                Linux Administrator's Manual                VMSTAT(8)



NAME
       vmstat - Report virtual memory statistics

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

DESCRIPTION
       vmstat  reports  information about processes, memory, paging, block IO,
       traps, and cpu activity.

       The first report produced gives averages since the last reboot.   Addi-
       tional  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 speci-
       fied, 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 bottlenecks.  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>.



Throatwobbler Ginkgo Labs        27 July 1994                        VMSTAT(8)