VMSTAT(8) BSD System Manager's Manual VMSTAT(8)NAMEvmstat - report virtual memory statistics
SYNOPSISvmstat [-ims] [-c count] [-M core] [-N system] [-w wait] [disks]
DESCRIPTION
The vmstat program reports certain kernel statistics kept about process,
virtual memory, disk, trap and cpu activity.
The options are as follows:
-c count 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 (see the -w option), the display will be repeated
each second.
-i Report on the number of interrupts taken by each device since
system startup.
-M core Extract values associated with the name list from the speci-
fied core instead of the default /dev/kmem.
-N system Extract the name list from the specified system instead of
the default /bsd.
-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.
-w wait Pause wait seconds between each display. If no repeat count
is specified (see the -c option) the display will be repeated
indefinitely.
By default, vmstat displays the following information:
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. Virtual
pages (reported in units of 1024 bytes) are considered active 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 av-
eraged each five seconds, and given in units per second.
flt total page faults (includes copy-on-write faults)
re pages reclaimed from the inactive list
pi pages paged in
po pages paged out
fr pages freed per second
sr pages considered for pageout
disks Disk operations per second (this field is system dependent).
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 displays only the first four drives. To force
vmstat to display specific drives, their names may be supplied on
the command line.
faults Trap/interrupt rate averages per second over last 5 seconds.
in device interrupts per interval (including clock inter-
rupts)
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
EXAMPLES
The command ``vmstat -w 5'' will print what the system is doing every
five seconds. Five seconds is a good choice of printing interval since
some of the statistics sampled in the system are only updated that often.
FILES
bsd default kernel namelist
/dev/kmem default memory file
SEE ALSOfstat(1), netstat(1), nfsstat(1), ps(1), systat(1), iostat(8),
pstat(8)
The sections starting with ``Interpreting system activity'' in Installing
and Operating 4.3BSD.
BUGS
The -c and -w options are only available with the default output.
BSDI BSD/OS November 9, 1996 2
