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1 | .\" Copyright (c) 1980 Regents of the University of California. |
2 | .\" All rights reserved. The Berkeley software License Agreement | |
3 | .\" specifies the terms and conditions for redistribution. | |
4 | .\" | |
7d8111ac | 5 | .\" @(#)vmstat.8 5.1 (Berkeley) %G% |
a5a04f92 | 6 | .\" |
7d8111ac | 7 | .TH VMSTAT 1 "26 April 1981" |
a5a04f92 KM |
8 | .UC 4 |
9 | .de s1 | |
10 | .if n .sp | |
11 | .if t .sp .1i | |
12 | .. | |
13 | .de t1 | |
14 | .if n .ta 5n | |
15 | .if t .ta 1i | |
16 | .. | |
17 | .SH NAME | |
18 | vmstat \- report virtual memory statistics | |
19 | .SH SYNOPSIS | |
20 | .B vmstat | |
21 | [ | |
22 | .B \-fs | |
23 | ] | |
24 | [ interval [ count ] ] | |
25 | .SH DESCRIPTION | |
26 | .I Vmstat | |
27 | delves into the system and normally reports certain statistics kept about | |
28 | process, virtual memory, disk, trap and cpu activity. | |
29 | If given a | |
30 | .B \-f | |
31 | argument, it instead reports on the number of | |
32 | .I forks | |
33 | and | |
34 | .I vforks | |
35 | since system startup and the number of pages of virtual memory involved in each | |
36 | kind of fork. | |
37 | If given a | |
38 | .B \-s | |
39 | argument, it instead prints the contents | |
40 | of the | |
41 | .I sum | |
42 | structure, giving the total number of several kinds of paging related | |
43 | events which have occurred since boot. | |
44 | .PP | |
45 | If none of these options are given, | |
46 | .I vmstat | |
7d8111ac KM |
47 | will report in the first line a summary of the virtual memory activity |
48 | since the system has been booted. | |
49 | If | |
a5a04f92 | 50 | .I interval |
7d8111ac | 51 | is specified, then successive lines are summaries over the last |
a5a04f92 | 52 | .I interval |
7d8111ac | 53 | seconds. |
a5a04f92 KM |
54 | ``vmstat 5'' will print what the system is doing every five seconds; |
55 | this is a good choice of printing interval since this is how often | |
56 | some of the statistics are sampled in the system; others vary every | |
57 | second, running the output for a while will make it apparent which | |
58 | are recomputed every second. | |
59 | If a | |
60 | .I count | |
61 | is given, the statistics are repeated | |
62 | .I count | |
63 | times. | |
64 | The format fields are: | |
65 | .PP | |
66 | Procs: information about numbers of processes in various states. | |
67 | .s1 | |
68 | .t1 | |
69 | .nf | |
70 | r in run queue | |
71 | b blocked for resources (i/o, paging, etc.) | |
72 | w runnable or short sleeper (< 20 secs) but swapped | |
73 | .fi | |
74 | .s1 | |
75 | Memory: information about the usage of virtual and real memory. | |
76 | Virtual pages are considered active if they belong to processes which | |
77 | are running or have run in the last 20 seconds. | |
78 | A ``page'' here is 1024 bytes. | |
79 | .s1 | |
80 | .t1 | |
81 | .nf | |
82 | avm active virtual pages | |
83 | fre size of the free list | |
84 | .fi | |
85 | .s1 | |
86 | Page: information about page faults and paging activity. | |
87 | These are averaged each five seconds, and given in units per second. | |
88 | .s1 | |
89 | .t1 | |
90 | .nf | |
91 | re page reclaims (simulating reference bits) | |
92 | pi pages paged in | |
93 | po pages paged out | |
94 | fr pages freed per second | |
95 | de anticipated short term memory shortfall | |
96 | sr pages scanned by clock algorithm, per-second | |
97 | .fi | |
98 | .s1 | |
99 | up/hp/rk: Disk operations per second (this field is system dependent). | |
100 | Typically paging will be split across several of the available drives. | |
101 | The number under each of these is the unit number. | |
102 | .s1 | |
103 | Faults: trap/interrupt rate averages per second over last 5 seconds. | |
104 | .s1 | |
105 | .t1 | |
106 | .nf | |
107 | in (non clock) device interrupts per second | |
108 | sy system calls per second | |
109 | cs cpu context switch rate (switches/sec) | |
110 | .fi | |
111 | .s1 | |
112 | Cpu: breakdown of percentage usage of CPU time | |
113 | .s1 | |
114 | .nf | |
115 | us user time for normal and low priority processes | |
116 | sy system time | |
117 | id cpu idle | |
118 | .SH FILES | |
119 | /dev/kmem, /vmunix | |
120 | .SH SEE ALSO | |
121 | The sections starting with ``Interpreting system activity'' in | |
7d8111ac | 122 | .IR "Installing and Operating 4.2bsd" . |
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123 | .SH AUTHORS |
124 | William Joy and Ozalp Babaoglu | |
125 | .SH BUGS | |
126 | There should be a screen oriented program which combines | |
127 | .I vmstat | |
128 | and | |
129 | .IR ps (1) | |
130 | in real time | |
131 | as well as reporting on other system activity. |