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32 .\" @(#)vmstat.8 8.1 (Berkeley) 6/6/93
33 .\" $FreeBSD: src/usr.bin/vmstat/vmstat.8,v 1.16.2.5 2001/08/16 13:17:13 ru Exp $
34 .\" $DragonFly: src/usr.bin/vmstat/vmstat.8,v 1.6 2008/09/02 11:50:46 matthias Exp $
41 .Nd report virtual memory statistics
60 reports certain kernel statistics kept about process, virtual memory,
61 disk, trap and cpu activity.
63 The options are as follows:
64 .Bl -tag -width indent
69 The first display is for the time since a reboot and each subsequent
70 report is for the time period since the last display.
75 is specified, the default is infinity, otherwise the default is one.
77 .\" Report on the number
81 .\" system calls since system startup, and the number of pages of virtual memory
84 Report on the number of interrupts taken by each device since system
87 Extract values associated with the name list from the specified
89 instead of the default
92 Extract the name list from the specified
94 instead of the default
97 Report on the usage of kernel dynamic memory listed first by size of
98 allocation and then by type of usage.
100 Change the maximum number of disks to display from the default of 2.
102 Specify which types of devices to display. There are three different
103 categories of devices:
105 .Bl -tag -width indent -compact
107 .Bl -tag -width 9n -compact
109 Direct Access devices
111 Sequential Access devices
117 Write Once Read Multiple devices
123 Optical Memory devices
125 Medium Changer devices
127 Communication devices
129 Storage Array devices
131 Enclosure Services devices
137 .Bl -tag -width 9n -compact
139 Integrated Drive Electronics devices
141 Small Computer System Interface devices
143 Any other device interface
147 .Bl -tag -width 9n -compact
153 The user must specify at least one device type, and may specify at most
154 one device type from each category. Multiple device types in a single
155 device type statement must be separated by commas.
159 arguments may be specified on the command line. All
161 arguments are ORed together to form a matching expression against which
162 all devices in the system are compared. Any device that fully matches
165 argument will be included in the
167 output, up to three devices, or the maximum number of devices specified
170 Display the contents of the
172 structure, giving the total number of several kinds of paging related
173 events which have occurred since system startup.
175 .\" Report on the number of page in and page reclaims since system startup,
176 .\" and the amount of time required by each.
178 If specified together with
180 include IRQ numbers before device names.
184 seconds between each display.
187 interval is specified, the default is 1 second.
189 Report on memory used by the kernel zone allocator, by zone.
190 The information shown is the same as that returned by the
197 displays the following information:
198 .Bl -tag -width indent
200 Information about the numbers of processes in various states.
202 .Bl -tag -width indent -compact
206 blocked for resources (i/o, paging, etc.)
208 runnable or short sleeper (< 20 secs) but swapped
211 Information about the usage of virtual and real memory.
212 Virtual pages (reported in units of 1024 bytes) are considered active if
213 they belong to processes which are running or have run in the last 20
216 .Bl -tag -width indent -compact
220 size of the free list
223 Information about page faults and paging activity.
224 These are averaged each five seconds, and given in units per second.
226 .Bl -tag -width indent -compact
228 total number of page faults
230 page reclaims (simulating reference bits)
232 .\" pages attached (found in free list)
238 pages freed per second
240 .\" anticipated short term memory shortfall
242 pages scanned by clock algorithm, per-second
245 Disk operations per second (this field is system dependent).
246 Typically paging will be split across the available drives.
247 The header of the field is the first two characters of the disk name and
249 If more than three disk drives are configured in the system,
251 displays only the first three drives, unless the user specifies the
253 argument to increase the number of drives displayed. This will probably
254 cause the display to exceed 80 columns, however.
257 to display specific drives, their names may be supplied on the command line.
259 defaults to show disks first, and then various other random devices in the
260 system to add up to three devices, if there are that many devices in the
261 system. If devices are specified on the command line, or if a device type
262 matching pattern is specified (see above),
264 will only display the given devices or the devices matching the pattern,
265 and will not randomly select other devices in the system.
267 Trap/interrupt rate averages per second over last 5 seconds.
269 .Bl -tag -width indent -compact
271 device interrupts per interval (including clock interrupts)
273 system calls per interval
275 cpu context switch rate (switches/interval)
278 Breakdown of percentage usage of CPU time.
280 .Bl -tag -width indent -compact
282 user time for normal and low priority processes
290 .Bl -tag -width /dev/kmemxxx -compact
292 default kernel namelist
299 will print what the system is doing every five
300 seconds; this is a good choice of printing interval since this is how often
301 some of the statistics are sampled in the system.
302 Others vary every second and running the output for a while will make it
303 apparent which are recomputed every second.
306 .Dl vmstat -p da -p cd -w 1
307 will tell vmstat to select the first three direct access or CDROM devices
308 and display statistics on those devices, as well as other systems
309 statistics every second.
320 The sections starting with ``Interpreting system activity'' in
321 .%T "Installing and Operating 4.3BSD" .
327 options are only available with the default output.