NAME

vmstat − report virtual memory statistics

SYNOPSIS

vmstat [[-dnS] [interval [count]] | -f | -s | -z]

DESCRIPTION

vmstat normally reports certain statistics kept about process, virtual memory, trap, and CPU activity. 

Options

vmstat recognizes the following options:

-d Report disk transfer information in the form of transfers per second. 

-n Provide an output format that is more easily viewed on an 80-column display device.  This format separates the report into two groups: virtual memory information and CPU data.  Each group is displayed as a separate line of output.  On multiprocessor systems, this display format also provides CPU utilization on a per CPU basis. 

-S Report the number of processes swapped in and out instead of page reclaims and address translation faults. 

interval Display successive lines which are summaries over the last interval seconds.  The command vmstat 5 prints 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. 

count Repeat the summary statistics count times. 

-f Report on the number of forks and the number of pages of virtual memory involved since boot-up. 

-s Print the contents of the sum structure, giving the total number of several kinds of paging-related events that have occurred since boot-up or since vmstat -z was last executed. 

-z Clear all accumulators in the sum structure.  This requires write file access permission on /dev/kmem.  This is normally restricted to users with appropriate privileges. 

If none of these options are given, vmstat reports in the first line a summary of the virtual memory activity since boot-up or since vmstat -z was last executed.  The column headings and the meanings of each column are:

Procs: Information about 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 swapped

Memory: Information about the usage of virtual and real memory.  Virtual pages are considered active if they belong to processes that are running or have run in the last 20 seconds. 

avm active virtual pages

free 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

at address translation faults

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

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

in (non clock) device interrupts per second

sy system calls per second

cs cpu context switch rate (switches/sec)

Cpu: Breakdown of percentage usage of CPU time

us user time for normal and low priority processes

sy system time

id CPU idle

DEPENDENCIES

Series 300/400

Disk transfer information is not yet reported for SCSI disks. 

AUTHOR

vmstat was developed by the University of California, Berkeley, and HP. 

FILES

/dev/kmem

SEE ALSO

iostat(1), privilege(5). 

Hewlett-Packard Company  —  HP-UX Release 9.03: April 1994