xref: /freebsd/usr.bin/vmstat/vmstat.8 (revision 8e537d168674d6b65869f73c20813001af875738)
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32.\"	@(#)vmstat.8	8.1 (Berkeley) 6/6/93
33.\"
34.Dd June 6, 1996
35.Dt VMSTAT 8
36.Os BSD 4
37.Sh NAME
38.Nm vmstat
39.Nd report virtual memory statistics
40.Sh SYNOPSIS
41.Nm vmstat
42.Op Fl fimst
43.Op Fl c Ar count
44.Op Fl M core
45.Op Fl N system
46.Op Fl w wait
47.Op Ar disks
48.Sh DESCRIPTION
49.Nm Vmstat
50reports certain kernel statistics kept about process, virtual memory,
51disk, trap and cpu activity.
52.Pp
53The options are as follows:
54.Bl -tag -width indent
55.It Fl c
56Repeat the display
57.Ar count
58times.
59The first display is for the time since a reboot and each subsequent report
60is for the time period since the last display.
61If no
62.Ar wait
63interval is specified, the default is 1 second.
64.It Fl f
65Report on the number
66.Xr fork 2
67and
68.Xr vfork 2
69system calls since system startup, and the number of pages of virtual memory
70involved in each.
71.It Fl i
72Report on the number of interrupts taken by each device since system
73startup.
74.It Fl M
75Extract values associated with the name list from the specified
76.Ar core
77instead of the default
78.Pa /dev/kmem .
79.It Fl N
80Extract the name list from the specified
81.Ar system
82instead of the default
83.Pa /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 s
88Display the contents of the
89.Em sum
90structure, giving the total number of several kinds of paging related
91events which have occurred since system startup.
92.It Fl t
93Report on the number of page in and page reclaims since system startup,
94and the amount of time required by each.
95.It Fl w
96Pause
97.Ar wait
98seconds between each display.
99If no repeat
100.Ar count
101is specified, the default is infinity.
102.El
103.Pp
104By default,
105.Nm vmstat
106displays the following information:
107.Pp
108.Bl -tag -width indent
109.It procs
110Information about the numbers of processes in various states.
111.Pp
112.Bl -tag -width indent -compact
113.It r
114in run queue
115.It b
116blocked for resources (i/o, paging, etc.)
117.It w
118runnable or short sleeper (< 20 secs) but swapped
119.El
120.It memory
121Information about the usage of virtual and real memory.
122Virtual pages (reported in units of 1024 bytes) are considered active if
123they belong to processes which are running or have run in the last 20
124seconds.
125.Pp
126.Bl -tag -width indent -compact
127.It avm
128active virtual pages
129.It fre
130size of the free list
131.El
132.It page
133Information about page faults and paging activity.
134These are averaged each five seconds, and given in units per second.
135.Pp
136.Bl -tag -width indent -compact
137.It re
138page reclaims (simulating reference bits)
139.It at
140pages attached (found in free list)
141.It pi
142pages paged in
143.It po
144pages paged out
145.It fr
146pages freed per second
147.It de
148anticipated short term memory shortfall
149.It sr
150pages scanned by clock algorithm, per-second
151.El
152.It disks
153Disk operations per second (this field is system dependent).
154Typically paging will be split across the available drives.
155The header of the field is the first character of the disk name and
156the unit number.
157If more than four disk drives are configured in the system,
158.Nm vmstat
159displays only the first four drives.
160To force
161.Nm vmstat
162to display specific drives, their names may be supplied on the command line.
163.It faults
164Trap/interrupt rate averages per second over last 5 seconds.
165.Pp
166.Bl -tag -width indent -compact
167.It in
168device interrupts per interval (including clock interrupts)
169.It sy
170system calls per interval
171.It cs
172cpu context switch rate (switches/interval)
173.El
174.It cpu
175Breakdown of percentage usage of CPU time.
176.Pp
177.Bl -tag -width indent -compact
178.It us
179user time for normal and low priority processes
180.It sy
181system time
182.It id
183cpu idle
184.El
185.El
186.Sh EXAMPLES
187The command:
188.Dl vmstat -w 5
189will print what the system is doing every five
190seconds; this is a good choice of printing interval since this is how often
191some of the statistics are sampled in the system.
192Others vary every second and running the output for a while will make it
193apparent which are recomputed every second.
194.Sh FILES
195.Bl -tag -width /dev/kmemxxx -compact
196.It Pa /kernel
197default kernel namelist
198.It Pa /dev/kmem
199default memory file
200.El
201.Sh SEE ALSO
202.Xr fstat 1 ,
203.Xr netstat 1 ,
204.Xr nfsstat 1 ,
205.Xr ps 1 ,
206.Xr systat 1 ,
207.Xr iostat 8 ,
208.Xr pstat 8
209.Pp
210The sections starting with ``Interpreting system activity'' in
211.%T "Installing and Operating 4.3BSD" .
212.SH BUGS
213The
214.Fl c
215and
216.Fl w
217options are only available with the default output.
218