xref: /dragonfly/lib/libc/sys/getrusage.2 (revision 984263bc)
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32.\"     @(#)getrusage.2	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD: src/lib/libc/sys/getrusage.2,v 1.10.2.5 2001/12/14 18:34:00 ru Exp $
34.\"
35.Dd June 4, 1993
36.Dt GETRUSAGE 2
37.Os
38.Sh NAME
39.Nm getrusage
40.Nd get information about resource utilization
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In sys/types.h
45.In sys/time.h
46.In sys/resource.h
47.Fd "#define	RUSAGE_SELF	 0"
48.Fd "#define	RUSAGE_CHILDREN	-1"
49.Ft int
50.Fn getrusage "int who" "struct rusage *rusage"
51.Sh DESCRIPTION
52.Fn Getrusage
53returns information describing the resources utilized by the current
54process, or all its terminated child processes.
55The
56.Fa who
57parameter is either
58.Dv RUSAGE_SELF
59or
60.Dv RUSAGE_CHILDREN .
61The buffer to which
62.Fa rusage
63points will be filled in with
64the following structure:
65.Bd -literal
66struct rusage {
67        struct timeval ru_utime; /* user time used */
68        struct timeval ru_stime; /* system time used */
69        long ru_maxrss;          /* max resident set size */
70        long ru_ixrss;           /* integral shared text memory size */
71        long ru_idrss;           /* integral unshared data size */
72        long ru_isrss;           /* integral unshared stack size */
73        long ru_minflt;          /* page reclaims */
74        long ru_majflt;          /* page faults */
75        long ru_nswap;           /* swaps */
76        long ru_inblock;         /* block input operations */
77        long ru_oublock;         /* block output operations */
78        long ru_msgsnd;          /* messages sent */
79        long ru_msgrcv;          /* messages received */
80        long ru_nsignals;        /* signals received */
81        long ru_nvcsw;           /* voluntary context switches */
82        long ru_nivcsw;          /* involuntary context switches */
83};
84.Ed
85.Pp
86The fields are interpreted as follows:
87.Bl -tag -width ru_minfltaa
88.It Fa ru_utime
89the total amount of time spent executing in user mode.
90.It Fa ru_stime
91the total amount of time spent in the system executing on behalf
92of the process(es).
93.It Fa ru_maxrss
94the maximum resident set size utilized (in kilobytes).
95.It Fa ru_ixrss
96an
97.Dq integral
98value indicating the amount of memory used
99by the text segment
100that was also shared among other processes.  This value is expressed
101in units of kilobytes * ticks-of-execution.
102Ticks are statistics clock ticks.
103The statistics clock has a frequency of
104.Fn sysconf _SC_CLOCK_TCK
105ticks per second.
106.It Fa ru_idrss
107an integral value of the amount of unshared memory residing in the
108data segment of a process (expressed in units of
109kilobytes * ticks-of-execution).
110.It Fa ru_isrss
111an integral value of the amount of unshared memory residing in the
112stack segment of a process (expressed in units of
113kilobytes * ticks-of-execution).
114.It Fa ru_minflt
115the number of page faults serviced without any I/O activity; here
116I/O activity is avoided by
117.Dq reclaiming
118a page frame from
119the list of pages awaiting reallocation.
120.It Fa ru_majflt
121the number of page faults serviced that required I/O activity.
122.It Fa ru_nswap
123the number of times a process was
124.Dq swapped
125out of main
126memory.
127.It Fa ru_inblock
128the number of times the file system had to perform input.
129.It Fa ru_oublock
130the number of times the file system had to perform output.
131.It Fa ru_msgsnd
132the number of IPC messages sent.
133.It Fa ru_msgrcv
134the number of IPC messages received.
135.It Fa ru_nsignals
136the number of signals delivered.
137.It Fa ru_nvcsw
138the number of times a context switch resulted due to a process
139voluntarily giving up the processor before its time slice was
140completed (usually to await availability of a resource).
141.It Fa ru_nivcsw
142the number of times a context switch resulted due to a higher
143priority process becoming runnable or because the current process
144exceeded its time slice.
145.El
146.Sh NOTES
147The numbers
148.Fa ru_inblock
149and
150.Fa ru_oublock
151account only for real
152I/O; data supplied by the caching mechanism is charged only
153to the first process to read or write the data.
154.Sh RETURN VALUES
155.Rv -std getrusage
156.Sh ERRORS
157The
158.Fn getrusage
159function will fail if:
160.Bl -tag -width Er
161.It Bq Er EINVAL
162The
163.Fa who
164parameter is not a valid value.
165.It Bq Er EFAULT
166The address specified by the
167.Fa rusage
168parameter is not in a valid part of the process address space.
169.El
170.Sh SEE ALSO
171.Xr gettimeofday 2 ,
172.Xr wait 2 ,
173.Xr clocks 7
174.Sh BUGS
175There is no way to obtain information about a child process
176that has not yet terminated.
177.Sh HISTORY
178The
179.Fn getrusage
180function call appeared in
181.Bx 4.2 .
182