xref: /minix3/lib/libc/sys/getrusage.2 (revision 2fe8fb192fe7e8720e3e7a77f928da545e872a6a)
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30.\"     @(#)getrusage.2	8.1 (Berkeley) 6/4/93
31.\"
32.Dd June 4, 1993
33.Dt GETRUSAGE 2
34.Os
35.Sh NAME
36.Nm getrusage
37.Nd get information about resource utilization
38.Sh LIBRARY
39.Lb libc
40.Sh SYNOPSIS
41.In sys/resource.h
42.Fd #define	RUSAGE_SELF	 0
43.Fd #define	RUSAGE_CHILDREN	\-1
44.Ft int
45.Fn getrusage "int who" "struct rusage *rusage"
46.Sh DESCRIPTION
47.Fn getrusage
48returns information describing the resources used by the current
49process, or all its terminated child processes.
50The
51.Fa who
52parameter is either
53.Dv RUSAGE_SELF
54or
55.Dv RUSAGE_CHILDREN .
56The buffer to which
57.Fa rusage
58points will be filled in with
59the following structure:
60.Bd -literal
61struct rusage {
62        struct timeval ru_utime; /* user time used */
63        struct timeval ru_stime; /* system time used */
64        long ru_maxrss;          /* max resident set size */
65        long ru_ixrss;           /* integral shared text memory size */
66        long ru_idrss;           /* integral unshared data size */
67        long ru_isrss;           /* integral unshared stack size */
68        long ru_minflt;          /* page reclaims */
69        long ru_majflt;          /* page faults */
70        long ru_nswap;           /* swaps */
71        long ru_inblock;         /* block input operations */
72        long ru_oublock;         /* block output operations */
73        long ru_msgsnd;          /* messages sent */
74        long ru_msgrcv;          /* messages received */
75        long ru_nsignals;        /* signals received */
76        long ru_nvcsw;           /* voluntary context switches */
77        long ru_nivcsw;          /* involuntary context switches */
78};
79.Ed
80.Pp
81The fields are interpreted as follows:
82.Bl -tag -width ru_minfltaa
83.It Fa ru_utime
84the total amount of time spent executing in user mode.
85.It Fa ru_stime
86the total amount of time spent in the system executing on behalf
87of the process(es).
88.It Fa ru_maxrss
89the maximum resident set size used (in kilobytes).
90.It Fa ru_ixrss
91an \*(lqintegral\*(rq value indicating the amount of memory used
92by the text segment
93that was also shared among other processes.
94This value is expressed
95in units of kilobytes * ticks-of-execution.
96.It Fa ru_idrss
97an integral value of the amount of unshared memory residing in the
98data segment of a process (expressed in units of
99kilobytes * ticks-of-execution).
100.It Fa ru_isrss
101an integral value of the amount of unshared memory residing in the
102stack segment of a process (expressed in units of
103kilobytes * ticks-of-execution).
104.It Fa ru_minflt
105the number of page faults serviced without any I/O activity; here
106I/O activity is avoided by \*(lqreclaiming\*(rq a page frame from
107the list of pages awaiting reallocation.
108.It Fa ru_majflt
109the number of page faults serviced that required I/O activity.
110.It Fa ru_nswap
111the number of times a process was \*(lqswapped\*(rq out of main
112memory.
113.It Fa ru_inblock
114the number of times the file system had to perform input.
115.It Fa ru_oublock
116the number of times the file system had to perform output.
117.It Fa ru_msgsnd
118the number of IPC messages sent.
119.It Fa ru_msgrcv
120the number of IPC messages received.
121.It Fa ru_nsignals
122the number of signals delivered.
123.It Fa ru_nvcsw
124the number of times a context switch resulted due to a process
125voluntarily giving up the processor before its time slice was
126completed (usually to await availability of a resource).
127.It Fa ru_nivcsw
128the number of times a context switch resulted due to a higher
129priority process becoming runnable or because the current process
130exceeded its time slice.
131.El
132.Sh NOTES
133The numbers
134.Fa ru_inblock
135and
136.Fa ru_oublock
137account only for real
138I/O; data supplied by the caching mechanism is charged only
139to the first process to read or write the data.
140.Sh ERRORS
141.Fn getrusage
142returns \-1 on error.
143The possible errors are:
144.Bl -tag -width Er
145.It Bq Er EINVAL
146The
147.Fa who
148parameter is not a valid value.
149.It Bq Er EFAULT
150The address specified by the
151.Fa rusage
152parameter is not in a valid part of the process address space.
153.El
154.Sh SEE ALSO
155.Xr gettimeofday 2 ,
156.Xr wait 2
157.Sh HISTORY
158The
159.Fn getrusage
160function call appeared in
161.Bx 4.2 .
162.Sh BUGS
163There is no way to obtain information about a child process
164that has not yet terminated.
165