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.\" 4. 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.\" @(#)vmstat.8 8.1 (Berkeley) 6/6/93 29.\" $FreeBSD$ 30.\" 31.Dd October 21, 2006 32.Dt VMSTAT 8 33.Os 34.Sh NAME 35.Nm vmstat 36.Nd report virtual memory statistics 37.Sh SYNOPSIS 38.Nm 39.\" .Op Fl fimst 40.Op Fl afHhimPsz 41.Op Fl c Ar count 42.Op Fl M Ar core Op Fl N Ar system 43.Op Fl w Ar wait 44.Op Fl n Ar devs 45.Oo 46.Fl p 47.Sm off 48.Ar type , if , pass 49.Sm on 50.Oc 51.Op Ar disks 52.Sh DESCRIPTION 53The 54.Nm 55utility reports certain kernel statistics kept about process, virtual memory, 56disk, trap and cpu activity. 57.Pp 58If the 59.Fl M 60option is not specified, information is obtained from 61the currently running kernel via the 62.Xr sysctl 3 63interface. 64Otherwise, information is read from the specified core file, 65using the name list from the specified kernel image (or from 66the default image). 67.Pp 68The options are as follows: 69.Bl -tag -width indent 70.It Fl a 71When used with 72.Fl i , 73include statistics about interrupts that have never been generated. 74.It Fl c 75Repeat the display 76.Ar count 77times. 78The first display is for the time since a reboot and each subsequent 79report is for the time period since the last display. 80If no repeat 81.Ar count 82is specified, and 83.Fl w 84is specified, the default is infinity, otherwise the default is one. 85.It Fl f 86Report on the number 87.Xr fork 2 , 88.Xr vfork 2 89and 90.Xr rfork 2 91system calls since system startup, and the number of pages of virtual memory 92involved in each. 93.It Fl h 94Changes memory columns into more easily human readable form. Default if 95standard output is a terminal device. 96.It Fl H 97Changes memory columns into straight numbers. Default if standard output 98is not a terminal device (such as a script). 99.It Fl i 100Report on the number of interrupts taken by each device since system 101startup. 102.It Fl M 103Extract values associated with the name list from the specified 104.Ar core . 105.It Fl N 106If 107.Fl M 108is also specified, 109extract the name list from the specified 110.Ar system 111instead of the default, 112which is the kernel image the system has booted from. 113.It Fl m 114Report on the usage of kernel dynamic memory allocated using 115.Xr malloc 9 116by type. 117.It Fl n 118Change the maximum number of disks to display from the default of 2. 119.It Fl P 120Report per-cpu system/user/idle cpu statistics. 121.It Fl p 122Specify which types of devices to display. 123There are three different 124categories of devices: 125.Pp 126.Bl -tag -width indent -compact 127.It device type: 128.Bl -tag -width 9n -compact 129.It da 130Direct Access devices 131.It sa 132Sequential Access devices 133.It printer 134Printers 135.It proc 136Processor devices 137.It worm 138Write Once Read Multiple devices 139.It cd 140CD devices 141.It scanner 142Scanner devices 143.It optical 144Optical Memory devices 145.It changer 146Medium Changer devices 147.It comm 148Communication devices 149.It array 150Storage Array devices 151.It enclosure 152Enclosure Services devices 153.It floppy 154Floppy devices 155.El 156.Pp 157.It interface: 158.Bl -tag -width 9n -compact 159.It IDE 160Integrated Drive Electronics devices 161.It SCSI 162Small Computer System Interface devices 163.It other 164Any other device interface 165.El 166.Pp 167.It passthrough: 168.Bl -tag -width 9n -compact 169.It pass 170Passthrough devices 171.El 172.El 173.Pp 174The user must specify at least one device type, and may specify at most 175one device type from each category. 176Multiple device types in a single 177device type statement must be separated by commas. 178.Pp 179Any number of 180.Fl p 181arguments may be specified on the command line. 182All 183.Fl p 184arguments are ORed together to form a matching expression against which 185all devices in the system are compared. 186Any device that fully matches 187any 188.Fl p 189argument will be included in the 190.Nm 191output, up to two devices, or the maximum number of devices specified 192by the user. 193.It Fl s 194Display the contents of the 195.Em sum 196structure, giving the total number of several kinds of paging related 197events which have occurred since system startup. 198.\" .It Fl t 199.\" Report on the number of page in and page reclaims since system startup, 200.\" and the amount of time required by each. 201.It Fl w 202Pause 203.Ar wait 204seconds between each display. 205If no repeat 206.Ar wait 207interval is specified, the default is 1 second. 208The 209.Nm 210command will accept and honor a non-integer number of seconds. 211.It Fl z 212Report on memory used by the kernel zone allocator, 213.Xr uma 9 , 214by zone. 215.El 216.Pp 217By default, 218.Nm 219displays the following information: 220.Bl -tag -width indent 221.It procs 222Information about the numbers of processes in various states. 223.Pp 224.Bl -tag -width indent -compact 225.It r 226in run queue 227.It b 228blocked for resources (i/o, paging, etc.) 229.It w 230runnable or short sleeper (< 20 secs) but swapped 231.El 232.It memory 233Information about the usage of virtual and real memory. 234Virtual pages (reported in units of 1024 bytes) are considered active if 235they belong to processes which are running or have run in the last 20 236seconds. 237.Pp 238.Bl -tag -width indent -compact 239.It avm 240active virtual pages 241.It fre 242size of the free list 243.El 244.It page 245Information about page faults and paging activity. 246These are averaged each five seconds, and given in units per second. 247.Pp 248.Bl -tag -width indent -compact 249.It flt 250total number of page faults 251.It re 252page reclaims (simulating reference bits) 253.\" .It at 254.\" pages attached (found in free list) 255.It pi 256pages paged in 257.It po 258pages paged out 259.It fr 260pages freed per second 261.\" .It de 262.\" anticipated short term memory shortfall 263.It sr 264pages scanned by clock algorithm, per-second 265.El 266.It disks 267Disk operations per second (this field is system dependent). 268Typically paging will be split across the available drives. 269The header of the field is the first two characters of the disk name and 270the unit number. 271If more than two disk drives are configured in the system, 272.Nm 273displays only the first two drives, unless the user specifies the 274.Fl n 275argument to increase the number of drives displayed. 276This will probably 277cause the display to exceed 80 columns, however. 278To force 279.Nm 280to display specific drives, their names may be supplied on the command line. 281The 282.Nm 283utility 284defaults to show disks first, and then various other random devices in the 285system to add up to two devices, if there are that many devices in the 286system. 287If devices are specified on the command line, or if a device type 288matching pattern is specified (see above), 289.Nm 290will only display the given devices or the devices matching the pattern, 291and will not randomly select other devices in the system. 292.It faults 293Trap/interrupt rate averages per second over last 5 seconds. 294.Pp 295.Bl -tag -width indent -compact 296.It in 297device interrupts per interval (including clock interrupts) 298.It sy 299system calls per interval 300.It cs 301cpu context switch rate (switches/interval) 302.El 303.It cpu 304Breakdown of percentage usage of CPU time. 305.Pp 306.Bl -tag -width indent -compact 307.It us 308user time for normal and low priority processes 309.It sy 310system time 311.It id 312cpu idle 313.El 314.El 315.Sh FILES 316.Bl -tag -width /boot/kernel/kernel -compact 317.It Pa /boot/kernel/kernel 318default kernel namelist 319.It Pa /dev/kmem 320default memory file 321.El 322.Sh EXAMPLES 323The command: 324.Dl vmstat -w 5 325will print what the system is doing every five 326seconds; this is a good choice of printing interval since this is how often 327some of the statistics are sampled in the system. 328Others vary every second and running the output for a while will make it 329apparent which are recomputed every second. 330.Pp 331The command: 332.Dl vmstat -p da -p cd -w 1 333will tell vmstat to select the first two direct access or CDROM devices 334and display statistics on those devices, as well as other systems 335statistics every second. 336.Sh SEE ALSO 337.Xr fstat 1 , 338.Xr netstat 1 , 339.Xr nfsstat 1 , 340.Xr ps 1 , 341.Xr systat 1 , 342.Xr libmemstat 3 , 343.Xr gstat 8 , 344.Xr iostat 8 , 345.Xr pstat 8 , 346.Xr sysctl 8 , 347.Xr malloc 9 , 348.Xr uma 9 349.Pp 350The sections starting with ``Interpreting system activity'' in 351.%T "Installing and Operating 4.3BSD" . 352.Sh BUGS 353The 354.Fl c 355and 356.Fl w 357options are only available with the default output. 358