.TH VMSTAT 8
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.UC
.SH NAME
vmstat \- report system and memory statistics
.SH SYNOPSIS
.B vmstat
[
.B \-sm
]
[ interval [ count ] ]
.SH DESCRIPTION
.I Vmstat
delves into the system and normally reports certain statistics kept about
process, memory and swap, disk, trap and cpu activity.
If given a
.B \-s
argument, it instead prints the contents
of the
.I sum
structure, giving the total number of several kinds of swap and cpu
events which have occurred since boot.
The
.B \-m
option causes it to print all of the memory usage statistics.
Memory usage is categorized as virtual and real,
active and inactive (for more than 20 seconds),
text and total, and free memory remaining.
Virtual memory is the sum of real memory and swap space in use.
The interval and count options are the same as below.
.PP
If neither option is given,
.I vmstat
will report in a (usually) iterative fashion on the
activity in the system.
In this case, the optional
.I interval
argument causes
.I vmstat
to report once each
.I interval
seconds;
``vmstat 5'' will print what the system is doing every five seconds;
this is a good choice of printing interval since this is how often
the statistics are sampled in the system.
If a
.I count
is given, the statistics are repeated
.I count
times.
The fields are:
.PP
Procs: information about numbers of processes in various states.
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RQ	in run queue
DW	disk wait
SW	runnable or short sleeper (< 20 secs) but swapped
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Memory: information about the usage of virtual and real memory.
Virtual pages are considered active if they belong to processes which
are running or have run in the last 20 seconds.
A ``page'' here is 1024 bytes.
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AVM	active virtual pages
TX	percent of active pages which are shared text
FRE	size of the free list
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Swap: information about the swapping activity of the system.
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I	process swap ins in last 5 seconds
O	process swap outs in last 5 seconds
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Disk: operations per second (this field is system dependent).
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D0	disk 0
D1	disk 1
D2	disk 2
D3	disk 3
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Faults: trap/interrupt, per second, over last 5 seconds.
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PD	pseudo-DMA interrupts from DZ-11's (per second)
IN	device interrupts (per second)
SY	system calls (per second)
TR	traps (per second)
OV	overlay traps (per second)
CS	cpu context switch rate (switches/sec)
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Cpu: breakdown of percentage usage of CPU time
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US	user time for normal processes
NI	user time for low priority processes
SY	system time
ID	cpu idle
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.SH FILES
/dev/kmem
.br
/unix
.SH BUGS
This program will only work if the information is maintained by the system;
some of this is optional and depends on the system configuration.