vmstat(8)
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VMSTAT(8) VMSTAT(8)
NAME
vmstat - report virtual memory statistics
SYNOPSIS
vmstat [ -efHilmsv ] [ -h histname ] [ -c count ] [ -M core ]
[ -N system ] [ -w wait ] [ disks ]
DESCRIPTION
Vmstat reports certain kernel statistics kept about pro-
cess, virtual memory, disk, trap and cpu activity.
The options are as follows:
-c 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 dis-
play. If no wait interval is specified, the
default is 1 second.
-e Report the values of system event counters.
-f Report fork statistics.
-i Report the values of system interrupt counters.
-M Extract values associated with the name list from
the specified core instead of the default
``/dev/mem''.
-N Extract the name list from the specified system
instead of the default ``/netbsd''.
-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 system startup.
-v Print more verbose information. When used with the
-i or -e flags, prints out all interrupts or event
counters, not just those with non-zero values.
-w Pause wait seconds between each display. If no
repeat count is specified, the default is infinity.
The following options only apply if vmstat was built with
support for UVM:
-l List the UVM histories being maintained by the ker-
nel.
-h Dump the specified UVM history.
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VMSTAT(8) VMSTAT(8)
-H Dump all UVM histories.
By default, vmstat displays the following information:
procs Information about the numbers of processes in vari-
ous 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 (reported in units of 1024
bytes) are considered active if they belong to pro-
cesses 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.
flt total page faults
re page reclaims (simulating reference bits)
pi pages paged in
po pages paged out
fr pages freed per second
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 sup-
plied on the command line.
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
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VMSTAT(8) VMSTAT(8)
EXAMPLES
The command ``vmstat -w 5'' will print what the system is
doing every five seconds; this is a good choice of print-
ing interval since this is how often some of the statis-
tics 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.
FILES
/netbsd default kernel namelist
/dev/mem default memory file
SEE ALSO
fstat(1), netstat(1), nfsstat(1), ps(1), systat(1),
iostat(8), pstat(8)
The sections starting with ``Interpreting system activ-
ity'' in Installing and Operating 4.3BSD.
BUGS
The -c and -w options are only available with the default
output.
February 12, 1998 3
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