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VMSTAT(8) OpenBSD System Manager's Manual VMSTAT(8)
vmstat - report virtual memory statistics
vmstat [-c count] [-M core] [-N system] [-w wait] [disks]
vmstat reports certain kernel statistics kept about process, virtual mem-
ory, disk, trap and cpu activity.
The options are as follows:
Repeat the display count times. The first display is for the time
since a reboot and each subsequent report is for the time period
since the last display. If no wait interval is specified, the de-
fault is 1 second.
-f Report on the number fork(2), vfork(2), and rfork(2) system calls
since system startup, and the number of pages of virtual memory in-
volved in each.
-i Report on the number of interrupts taken by each device since sys-
Extract values associated with the name list from the specified
core instead of the default /dev/mem.
Extract the name list from the specified system instead of the de-
-m Report on the usage of kernel dynamic memory listed first by size
of allocation and then by type of usage.
-s Display the contents of the sum structure, giving the total number
of several kinds of paging related events which have occurred since
-t Report on the number of page in and page reclaims since system
startup, and the amount of time required by each.
Pause wait seconds between each display. If no repeat count is
specified, the default is infinity.
By default, vmstat displays the following information just once:
procs Information about the 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. Virtu-
al pages (reported in units of 1024 bytes) are considered ac-
tive if they belong to processes which are running or have run
in the last 20 seconds.
avm active virtual pages
fre 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 (simulating reference bits)
at pages attached (found in free list)
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
disks Disk transfers per second. Typically paging will be split
across the available drives. The header of the field is the
first character of the disk name and the unit number. If more
than four disk drives are configured in the system, vmstat dis-
plays only the first four drives. To force vmstat to display
specific drives, their names may be supplied on the command
faults Trap/interrupt rate averages per second over last 5 seconds.
in device interrupts per interval (including clock interrupts)
sy system calls per interval
cs cpu context switch rate (switches/interval)
cpu Breakdown of percentage usage of CPU time.
us user time for normal and low priority processes
sy system time
id cpu idle
The command ``vmstat -w 5'' will print 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 and running the output for a while will make it apparent
which are recomputed every second.
/bsd Default kernel namelist
/dev/mem Default memory file
fstat(1), netstat(1), nfsstat(1), ps(1), systat(1), iostat(8),
The sections starting with ``Interpreting system activity'' in
The -c and -w options are only available with the default output.
This manual page lacks an incredible amount of detail.
OpenBSD 2.3 June 6, 1993 2
Source: OpenBSD 2.6 man pages. Copyright: Portions are copyrighted by BERKELEY
SOFTWARE DESIGN, INC., The Regents of the University of California, Massachusetts
Institute of Technology, Free Software Foundation, FreeBSD Inc., and others.
(Corrections, notes, and links courtesy of RocketAware.com)
FreeBSD Sources for vmstat(8)
OpenBSD sources for vmstat(8)
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