1.\" $OpenBSD: vmstat.8,v 1.40 2019/12/06 19:15:16 jmc Exp $ 2.\" $NetBSD: vmstat.8,v 1.12 1996/05/10 23:19:30 thorpej Exp $ 3.\" 4.\" Copyright (c) 1986, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)vmstat.8 8.1 (Berkeley) 6/6/93 32.\" 33.Dd $Mdocdate: December 6 2019 $ 34.Dt VMSTAT 8 35.Os 36.Sh NAME 37.Nm vmstat 38.Nd report statistics about kernel activities 39.Sh SYNOPSIS 40.Nm vmstat 41.Op Fl fimstvz 42.Nm vmstat 43.Op Fl c Ar count 44.Op Fl M Ar core 45.Op Fl N Ar system 46.Op Fl w Ar wait 47.Op Ar disk ... 48.Sh DESCRIPTION 49.Nm 50reports certain kernel statistics kept about process, virtual memory, 51disk, trap, and CPU activity. 52The default behavior is to print a one-line summary of these statistics. 53The 54.Fl c 55and 56.Fl w 57flags may be used to continually report summaries. 58.Pp 59The options are as follows: 60.Bl -tag -width Ds 61.It Fl c Ar count 62Repeat the display 63.Ar count 64times. 65The first display is for the time since a reboot and each subsequent report 66is for the time period since the last display. 67If no 68.Ar wait 69interval is specified, the default is 1 second. 70.It Fl f 71Report on the number of 72.Xr fork 2 , 73.Xr __tfork 3 , 74and 75.Xr vfork 2 76system calls as well as kernel thread creations since system startup, 77and the number of pages of virtual memory involved in each. 78.It Fl i 79Report on the number of interrupts taken by each device since system 80startup. 81.It Fl M Ar core 82Extract values associated with the name list from the specified core 83instead of the running kernel. 84.It Fl m 85Report on the usage of kernel dynamic memory listed first by size of 86allocation and then by type of usage. 87.It Fl N Ar system 88Extract the name list from the specified system instead of the running kernel. 89.It Fl s 90Display the contents of the 91.Va uvmexp 92structure (see 93.Xr uvm_init 9 ) , 94giving the total number of several kinds of paging related 95events which have occurred since system startup. 96.It Fl t 97Report on the number of page in and page reclaims since system startup, 98and the amount of time required by each. 99.It Fl v 100Print more verbose information. 101.It Fl w Ar wait 102Pause 103.Ar wait 104seconds between each display. 105If no repeat 106.Ar count 107is specified, the default is infinity. 108.It Fl z 109When used with 110.Fl i , 111also list devices which have not yet generated an interrupt. 112.El 113.Pp 114By default, 115.Nm 116displays the following information just once: 117.Bl -tag -width Ds 118.It Li procs 119Information about the numbers of processes in various states. 120.Pp 121.Bl -tag -width 4n -compact 122.It Li r 123in run queue 124.It Li s 125sleeping 126.El 127.It Li memory 128Information about the usage of virtual and real memory. 129.Pp 130.Bl -tag -width 4n -compact 131.It Li avm 132active virtual pages 133.It Li fre 134size of the free list 135.El 136.It Li page 137Information about page faults and paging activity. 138These are averaged each five seconds, and given in units per second. 139.Pp 140.Bl -tag -width 4n -compact 141.It Li flt 142page faults 143.It Li re 144page reclaims (simulating reference bits) 145.It Li pi 146pages paged in 147.It Li po 148pages paged out 149.It Li fr 150pages freed 151.It Li sr 152pages scanned by clock algorithm 153.El 154.It Li disks 155Disk transfers per second. 156Typically paging will be split across the available drives. 157The header of the field is the first character of the disk name and 158the unit number. 159If more than two disk drives are configured in the system, 160.Nm 161displays only the first two drives. 162To force 163.Nm 164to display specific drives, their names may be supplied on the command line. 165.It Li traps 166Trap/interrupt rate averages per second over last 5 seconds. 167.Pp 168.Bl -tag -width 4n -compact 169.It Li int 170device interrupts per interval (including clock interrupts) 171.It Li sys 172system calls per interval 173.It Li cs 174CPU context switch rate (switches/interval) 175.El 176.It Li cpu 177Breakdown of percentage usage of CPU time. 178.Pp 179.Bl -tag -width 4n -compact 180.It Li us 181user time for normal and low priority processes 182.It Li sy 183system time 184.It Li id 185CPU idle 186.El 187.El 188.Sh FILES 189.Bl -tag -width Pa -compact 190.It Pa /bsd 191default kernel image 192.It Pa /dev/kmem 193default memory file 194.El 195.Sh EXAMPLES 196The command 197.Ic vmstat -w 5 198will print what the system is doing every five 199seconds; this is a good choice of printing interval since this is how often 200some of the statistics are sampled in the system. 201Others vary every second and running the output for a while will make it 202apparent which are recomputed every second. 203.Sh SEE ALSO 204.Xr fstat 1 , 205.Xr netstat 1 , 206.Xr nfsstat 1 , 207.Xr procmap 1 , 208.Xr ps 1 , 209.Xr systat 1 , 210.Xr top 1 , 211.Xr iostat 8 , 212.Xr pstat 8 , 213.Xr uvm_init 9 214.Sh BUGS 215The 216.Fl c 217and 218.Fl w 219options are only available with the default output. 220.Pp 221This manual page lacks an incredible amount of detail. 222