1.\" Copyright (c) 1986, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)vmstat.8 8.1 (Berkeley) 6/6/93 33.\" $FreeBSD$ 34.\" 35.Dd October 21, 2006 36.Dt VMSTAT 8 37.Os 38.Sh NAME 39.Nm vmstat 40.Nd report virtual memory statistics 41.Sh SYNOPSIS 42.Nm 43.\" .Op Fl fimst 44.Op Fl afHhimPsz 45.Op Fl c Ar count 46.Op Fl M Ar core Op Fl N Ar system 47.Op Fl w Ar wait 48.Op Fl n Ar devs 49.Oo 50.Fl p 51.Sm off 52.Ar type , if , pass 53.Sm on 54.Oc 55.Op Ar disks 56.Sh DESCRIPTION 57The 58.Nm 59utility reports certain kernel statistics kept about process, virtual memory, 60disk, trap and cpu activity. 61.Pp 62If the 63.Fl M 64option is not specified, information is obtained from 65the currently running kernel via the 66.Xr sysctl 3 67interface. 68Otherwise, information is read from the specified core file, 69using the name list from the specified kernel image (or from 70the default image). 71.Pp 72The options are as follows: 73.Bl -tag -width indent 74.It Fl a 75When used with 76.Fl i , 77include statistics about interrupts that have never been generated. 78.It Fl c 79Repeat the display 80.Ar count 81times. 82The first display is for the time since a reboot and each subsequent 83report is for the time period since the last display. 84If no repeat 85.Ar count 86is specified, and 87.Fl w 88is specified, the default is infinity, otherwise the default is one. 89.It Fl f 90Report on the number 91.Xr fork 2 , 92.Xr vfork 2 93and 94.Xr rfork 2 95system calls since system startup, and the number of pages of virtual memory 96involved in each. 97.It Fl h 98Changes memory columns into more easily human readable form. Default if 99standard output is a terminal device. 100.It Fl H 101Changes memory columns into straight numbers. Default if standard output 102is not a terminal device (such as a script). 103.It Fl i 104Report on the number of interrupts taken by each device since system 105startup. 106.It Fl M 107Extract values associated with the name list from the specified 108.Ar core . 109.It Fl N 110If 111.Fl M 112is also specified, 113extract the name list from the specified 114.Ar system 115instead of the default, 116which is the kernel image the system has booted from. 117.It Fl m 118Report on the usage of kernel dynamic memory allocated using 119.Xr malloc 9 120by type. 121.It Fl n 122Change the maximum number of disks to display from the default of 2. 123.It Fl P 124Report per-cpu system/user/idle cpu statistics. 125.It Fl p 126Specify which types of devices to display. 127There are three different 128categories of devices: 129.Pp 130.Bl -tag -width indent -compact 131.It device type: 132.Bl -tag -width 9n -compact 133.It da 134Direct Access devices 135.It sa 136Sequential Access devices 137.It printer 138Printers 139.It proc 140Processor devices 141.It worm 142Write Once Read Multiple devices 143.It cd 144CD devices 145.It scanner 146Scanner devices 147.It optical 148Optical Memory devices 149.It changer 150Medium Changer devices 151.It comm 152Communication devices 153.It array 154Storage Array devices 155.It enclosure 156Enclosure Services devices 157.It floppy 158Floppy devices 159.El 160.Pp 161.It interface: 162.Bl -tag -width 9n -compact 163.It IDE 164Integrated Drive Electronics devices 165.It SCSI 166Small Computer System Interface devices 167.It other 168Any other device interface 169.El 170.Pp 171.It passthrough: 172.Bl -tag -width 9n -compact 173.It pass 174Passthrough devices 175.El 176.El 177.Pp 178The user must specify at least one device type, and may specify at most 179one device type from each category. 180Multiple device types in a single 181device type statement must be separated by commas. 182.Pp 183Any number of 184.Fl p 185arguments may be specified on the command line. 186All 187.Fl p 188arguments are ORed together to form a matching expression against which 189all devices in the system are compared. 190Any device that fully matches 191any 192.Fl p 193argument will be included in the 194.Nm 195output, up to two devices, or the maximum number of devices specified 196by the user. 197.It Fl s 198Display the contents of the 199.Em sum 200structure, giving the total number of several kinds of paging related 201events which have occurred since system startup. 202.\" .It Fl t 203.\" Report on the number of page in and page reclaims since system startup, 204.\" and the amount of time required by each. 205.It Fl w 206Pause 207.Ar wait 208seconds between each display. 209If no repeat 210.Ar wait 211interval is specified, the default is 1 second. 212The 213.Nm 214command will accept and honor a non-integer number of seconds. 215.It Fl z 216Report on memory used by the kernel zone allocator, 217.Xr uma 9 , 218by zone. 219.El 220.Pp 221By default, 222.Nm 223displays the following information: 224.Pp 225.Bl -tag -width indent 226.It procs 227Information about the numbers of processes in various states. 228.Pp 229.Bl -tag -width indent -compact 230.It r 231in run queue 232.It b 233blocked for resources (i/o, paging, etc.) 234.It w 235runnable or short sleeper (< 20 secs) but swapped 236.El 237.It memory 238Information about the usage of virtual and real memory. 239Virtual pages (reported in units of 1024 bytes) are considered active if 240they belong to processes which are running or have run in the last 20 241seconds. 242.Pp 243.Bl -tag -width indent -compact 244.It avm 245active virtual pages 246.It fre 247size of the free list 248.El 249.It page 250Information about page faults and paging activity. 251These are averaged each five seconds, and given in units per second. 252.Pp 253.Bl -tag -width indent -compact 254.It flt 255total number of page faults 256.It re 257page reclaims (simulating reference bits) 258.\" .It at 259.\" pages attached (found in free list) 260.It pi 261pages paged in 262.It po 263pages paged out 264.It fr 265pages freed per second 266.\" .It de 267.\" anticipated short term memory shortfall 268.It sr 269pages scanned by clock algorithm, per-second 270.El 271.It disks 272Disk operations per second (this field is system dependent). 273Typically paging will be split across the available drives. 274The header of the field is the first two characters of the disk name and 275the unit number. 276If more than two disk drives are configured in the system, 277.Nm 278displays only the first two drives, unless the user specifies the 279.Fl n 280argument to increase the number of drives displayed. 281This will probably 282cause the display to exceed 80 columns, however. 283To force 284.Nm 285to display specific drives, their names may be supplied on the command line. 286The 287.Nm 288utility 289defaults to show disks first, and then various other random devices in the 290system to add up to two devices, if there are that many devices in the 291system. 292If devices are specified on the command line, or if a device type 293matching pattern is specified (see above), 294.Nm 295will only display the given devices or the devices matching the pattern, 296and will not randomly select other devices in the system. 297.It faults 298Trap/interrupt rate averages per second over last 5 seconds. 299.Pp 300.Bl -tag -width indent -compact 301.It in 302device interrupts per interval (including clock interrupts) 303.It sy 304system calls per interval 305.It cs 306cpu context switch rate (switches/interval) 307.El 308.It cpu 309Breakdown of percentage usage of CPU time. 310.Pp 311.Bl -tag -width indent -compact 312.It us 313user time for normal and low priority processes 314.It sy 315system time 316.It id 317cpu idle 318.El 319.El 320.Sh FILES 321.Bl -tag -width /boot/kernel/kernel -compact 322.It Pa /boot/kernel/kernel 323default kernel namelist 324.It Pa /dev/kmem 325default memory file 326.El 327.Sh EXAMPLES 328The command: 329.Dl vmstat -w 5 330will print what the system is doing every five 331seconds; this is a good choice of printing interval since this is how often 332some of the statistics are sampled in the system. 333Others vary every second and running the output for a while will make it 334apparent which are recomputed every second. 335.Pp 336The command: 337.Dl vmstat -p da -p cd -w 1 338will tell vmstat to select the first two direct access or CDROM devices 339and display statistics on those devices, as well as other systems 340statistics every second. 341.Sh SEE ALSO 342.Xr fstat 1 , 343.Xr netstat 1 , 344.Xr nfsstat 1 , 345.Xr ps 1 , 346.Xr systat 1 , 347.Xr libmemstat 3 , 348.Xr gstat 8 , 349.Xr iostat 8 , 350.Xr pstat 8 , 351.Xr sysctl 8 , 352.Xr malloc 9 , 353.Xr uma 9 354.Pp 355The sections starting with ``Interpreting system activity'' in 356.%T "Installing and Operating 4.3BSD" . 357.Sh BUGS 358The 359.Fl c 360and 361.Fl w 362options are only available with the default output. 363