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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd June 21, 2021 29.Dt VMSTAT 8 30.Os 31.Sh NAME 32.Nm vmstat 33.Nd report virtual memory statistics 34.Sh SYNOPSIS 35.Nm 36.\" .Op Fl fimst 37.Op Fl -libxo 38.Op Fl afHhimoPsz 39.Op Fl M Ar core Op Fl N Ar system 40.Op Fl c Ar count 41.Op Fl n Ar devs 42.Oo 43.Fl p 44.Sm off 45.Ar type , if , pass 46.Sm on 47.Oc 48.Op Fl w Ar wait 49.Op Ar disks ... 50.Op wait Op count 51.Sh DESCRIPTION 52The 53.Nm 54utility reports certain kernel statistics kept about process, virtual memory, 55disk, trap and cpu activity. 56.Pp 57If the 58.Fl M 59option is not specified, information is obtained from 60the currently running kernel via the 61.Xr sysctl 3 62interface. 63Otherwise, information is read from the specified core file, 64using the name list from the specified kernel image (or from 65the default image). 66.Pp 67The options are as follows: 68.Bl -tag -width indent 69.It Fl -libxo 70Generate output via 71.Xr libxo 3 72in a selection of different human and machine readable formats. 73See 74.Xr xo_parse_args 3 75for details on command line arguments. 76.It Fl a 77When used with 78.Fl i , 79include statistics about interrupts that have never been generated. 80.It Fl c 81Repeat the display 82.Ar count 83times. 84The first display is for the time since a reboot and each subsequent 85report is for the time period since the last display. 86If no repeat 87.Ar count 88is specified, and 89.Fl w 90is specified, the default is infinity, otherwise the default is one. 91.It Fl f 92Report on the number 93.Xr fork 2 , 94.Xr vfork 2 95and 96.Xr rfork 2 97system calls since system startup, and the number of pages of virtual memory 98involved in each. 99.It Fl h 100Changes memory columns into more easily human readable form. 101The default if 102standard output is a terminal device. 103.It Fl H 104Changes memory columns into straight numbers. 105The default if standard output 106is not a terminal device (such as a script). 107.It Fl i 108Report on the number of interrupts taken by each device since system 109startup. 110.It Fl M 111Extract values associated with the name list from the specified 112.Ar core . 113.It Fl N 114If 115.Fl M 116is also specified, 117extract the name list from the specified 118.Ar system 119instead of the default, 120which is the kernel image the system has booted from. 121.It Fl m 122Report on the usage of kernel dynamic memory allocated using 123.Xr malloc 9 124by type. 125.It Fl n 126Change the maximum number of disks to display from the default of 2. 127.It Fl o 128Display a list of virtual memory objects in the system and the resident 129memory used by each object. 130.It Fl P 131Report per-cpu system/user/idle cpu statistics. 132.It Fl p 133Specify which types of devices to display. 134There are three different 135categories of devices: 136.Pp 137.Bl -tag -width indent -compact 138.It device type: 139.Bl -tag -width 9n -compact 140.It da 141Direct Access devices 142.It sa 143Sequential Access devices 144.It printer 145Printers 146.It proc 147Processor devices 148.It worm 149Write Once Read Multiple devices 150.It cd 151CD devices 152.It scanner 153Scanner devices 154.It optical 155Optical Memory devices 156.It changer 157Medium Changer devices 158.It comm 159Communication devices 160.It array 161Storage Array devices 162.It enclosure 163Enclosure Services devices 164.It floppy 165Floppy devices 166.El 167.Pp 168.It interface: 169.Bl -tag -width 9n -compact 170.It IDE 171Integrated Drive Electronics devices 172.It SCSI 173Small Computer System Interface devices 174.It NVME 175NVM Express Interface devices 176.It other 177Any other device interface 178.El 179.Pp 180.It passthrough: 181.Bl -tag -width 9n -compact 182.It pass 183Passthrough devices 184.El 185.El 186.Pp 187The user must specify at least one device type, and may specify at most 188one device type from each category. 189Multiple device types in a single 190device type statement must be separated by commas. 191.Pp 192Any number of 193.Fl p 194arguments may be specified on the command line. 195All 196.Fl p 197arguments are ORed together to form a matching expression against which 198all devices in the system are compared. 199Any device that fully matches 200any 201.Fl p 202argument will be included in the 203.Nm 204output, up to two devices, or the maximum number of devices specified 205by the user. 206.It Fl s 207Display the contents of the 208.Em sum 209structure, giving the total number of several kinds of paging related 210events which have occurred since system startup. 211.It Fl w 212Pause 213.Ar wait 214seconds between each display. 215If no repeat 216.Ar wait 217interval is specified, the default is 1 second. 218The 219.Nm 220command will accept and honor a non-integer number of seconds. 221.It Fl z 222Report on memory used by the kernel zone allocator, 223.Xr uma 9 , 224by zone. 225.El 226.Pp 227The 228.Ar wait 229and 230.Ar count 231arguments may be given after their respective flags at any point 232on the command line before the 233.Ar disks 234argument(s), or without their flags, as the final argument(s). 235The latter form is accepted for backwards compatibility, but it is 236preferred to use the forms with 237.Fl w 238and 239.Fl c 240to avoid ambiguity. 241.Pp 242By default, 243.Nm 244displays the following information: 245.Bl -tag -width indent 246.It procs 247Information about the number of threads in various states: 248.Pp 249.Bl -tag -width indent -compact 250.It r 251running or in run queue 252.It b 253blocked for resources (i/o, paging, etc.) 254.It w 255swapped out 256.El 257.It memory 258Information about the usage of virtual and real memory. 259.Pp 260Mapped virtual memory is a sum of all of the virtual pages belonging 261to mapped virtual memory objects. 262Note that the entire memory object's size is considered mapped even if 263only a subset of the object's pages are currently mapped. 264This statistic is not related to the active page queue which is used to track 265real memory. 266.Pp 267.Bl -tag -width indent -compact 268.It avm 269mapped virtual memory 270.Po previously called active in 271.Nm 272output 273.Pc 274.It fre 275size of the free list 276.El 277.It page 278Information about page faults and paging activity. 279These are given in units per second. 280.Pp 281.Bl -tag -width indent -compact 282.It flt 283total number of page faults 284.It re 285pages reactivated (found in laundry or inactive queues) 286.\" .It at 287.\" pages attached (found in free list) 288.It pi 289pages paged in 290.It po 291pages paged out 292.It fr 293pages freed 294.\" .It de 295.\" anticipated short term memory shortfall 296.It sr 297pages scanned by page daemon 298.El 299.It disks 300Disk operations per second (this field is system dependent). 301Typically paging will be split across the available drives. 302The header of the field is the first two characters of the disk name and 303the unit number. 304If more than two disk drives are configured in the system, 305.Nm 306displays only the first two drives, unless the user specifies the 307.Fl n 308argument to increase the number of drives displayed. 309This will probably 310cause the display to exceed 80 columns, however. 311To force 312.Nm 313to display specific drives, their names may be supplied on the command line. 314The 315.Nm 316utility 317defaults to show disks first, and then various other random devices in the 318system to add up to two devices, if there are that many devices in the 319system. 320If devices are specified on the command line, or if a device type 321matching pattern is specified (see above), 322.Nm 323will only display the given devices or the devices matching the pattern, 324and will not randomly select other devices in the system. 325.It faults 326Trap/interrupt rates per second. 327.Pp 328.Bl -tag -width indent -compact 329.It in 330device interrupts (including clock interrupts) 331.It sy 332system calls 333.It cs 334cpu context switches 335.El 336.It cpu 337Breakdown of percentage usage of CPU time. 338.Pp 339.Bl -tag -width indent -compact 340.It us 341user time for normal and low priority processes 342.It sy 343system and interrupt time 344.It id 345cpu idle 346.El 347.El 348.Sh FILES 349.Bl -tag -width /boot/kernel/kernel -compact 350.It Pa /boot/kernel/kernel 351default kernel namelist 352.It Pa /dev/kmem 353default memory file 354.El 355.Sh EXAMPLES 356The command: 357.Dl vmstat -w 5 358will print what the system is doing every five 359seconds. 360.Pp 361The command: 362.Dl vmstat -p da -p cd -w 1 363will tell vmstat to select the first two direct access or CDROM devices 364and display statistics on those devices, as well as other systems 365statistics every second. 366.Sh SEE ALSO 367.Xr fstat 1 , 368.Xr netstat 1 , 369.Xr nfsstat 1 , 370.Xr ps 1 , 371.Xr systat 1 , 372.Xr libmemstat 3 , 373.Xr libxo 3 , 374.Xr xo_parse_args 3 , 375.Xr gstat 8 , 376.Xr iostat 8 , 377.Xr pstat 8 , 378.Xr sysctl 8 , 379.Xr malloc 9 , 380.Xr uma 9 381.Pp 382The sections starting with ``Interpreting system activity'' in 383.%T "Installing and Operating 4.3BSD" . 384.Sh HISTORY 385The 386.Nm 387utility first appeared in 388.Bx 3 . 389.Sh BUGS 390The 391.Fl c 392and 393.Fl w 394options are only available with the default output. 395