VMSTAT(8) System Manager's Manual VMSTAT(8)
vmstat - report virtual memory statistics
vmstat [ -cfisS ] [ interval [ count ] ]
vmstat delves into the system and normally reports certain statistics
kept about process, virtual memory, disk, trap and CPU activity.
Without options, vmstat displays a one-line summary of the virtual mem-
ory activity since the system has been booted. If interval is speci-
fied, vmstat summarizes activity over the last interval seconds. If a
count is given, the statistics are repeated count times.
For example, the following command displays a summary of what the sys-
tem 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
example% vmstat 5
procs memory page faults
r b w avm fre re at pi po fr de sr x0 x1 x2 x3 in sy cs us sy id
2 0 0 918 286 0 0 0 0 0 0 0 1 0 0 0 4 12 5 3 5 91
1 0 0 846 254 0 0 0 0 0 0 0 6 0 1 0 42 153 31 7 40 54
1 0 0 840 268 0 0 0 0 0 0 0 5 0 0 0 27 103 25 8 26 66
1 0 0 620 312 0 0 0 0 0 0 0 6 0 0 0 26 76 25 6 27 67
The fields of vmstat's display are:
procs Report the number of processes in each of the three following
r in run queue
b blocked for resources (i/o, paging, etc.)
w runnable or short sleeper (< 20 secs) but swapped
memory Report on usage of virtual and real memory. Virtual memory is
considered active if it belongs to processes which are running
or have run in the last 20 seconds.
avm number of active virtual Kbytes
fre size of the free list in Kbytes
page Report information about page faults and paging activity. The
information on each of the following activities is averaged
each five seconds, and given in units per second.
re page reclaims -- but see the -S option for how this
field is modified.
at number of attaches -- but see the -S option for how
this field is modified.
pi kilobytes per second paged in
po kilobytes per second paged out
fr kilobytes freed per second
de anticipated short term memory shortfall in Kbytes
sr pages scanned by clock algorithm, per-second
disk Report number of disk operations per second (this field is sys-
tem dependent). For Sun systems, four slots are available for
up to four drives: ``x0'' (or ``s0'' for SCSI disks), ``x1'',
``x2'', and ``x3''.
faults Report trap/interrupt rate averages per second over last 5 sec-
in (non clock) device interrupts per second
sy system calls per second
cs CPU context switch rate (switches/sec)
cpu Give a breakdown of percentage usage of CPU time.
us user time for normal and low priority processes
sy system time
id CPU idle
-c Report cache flushing statistics. By default, report the total
number of each kind of cache flushed since boot time. The types
are: user, context, region, segment, page, and partial-page.
-f Report on the number of forks and vforks since system startup
and the number of pages of virtual memory involved in each kind
-i Report the number of interrupts per device. Autovectored inter-
rupts (including the clock) are listed first.
-s Display the contents of the sum structure, giving the total num-
ber of several kinds of paging-related events which have
occurred since boot.
-S Report on swapping rather than paging activity. This option
will change two fields in vmstat's ``paging'' display: rather
than the ``re'' and ``at'' fields, vmstat will report ``si''
(swap-ins), and ``so'' (swap-outs).
If more than one autovectored device has the same name, interrupts are
counted for all like-named devices regardless of unit number. Such
devices are listed with a unit number of `?'.
7 September 1988 VMSTAT(8)