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GETRUSAGE (2) | System calls | Unix Manual Pages | :man

NAME

getrusage - get information about resource utilization

CONTENTS

Library
Synopsis
Description
Notes
Return Values
Errors
See Also
History
Bugs

LIBRARY


.Lb libc

SYNOPSIS


.In sys/types.h
.In sys/time.h
.In sys/resource.h
.Fd "#define RUSAGE_SELF 0"
.Fd "#define RUSAGE_CHILDREN -1" int getrusage "int who" "struct rusage *rusage"

DESCRIPTION

The getrusage system call returns information describing the resources utilized by the current process, or all its terminated child processes. The who argument is either RUSAGE_SELF or RUSAGE_CHILDREN. The buffer to which rusage points will be filled in with the following structure:
struct rusage {
struct timeval ru_utime; /* user time used */
struct timeval ru_stime; /* system time used */
long ru_maxrss;/* max resident set size */
long ru_ixrss; /* integral shared text memory size */
long ru_idrss; /* integral unshared data size */
long ru_isrss; /* integral unshared stack size */
long ru_minflt;/* page reclaims */
long ru_majflt;/* page faults */
long ru_nswap; /* swaps */
long ru_inblock; /* block input operations */
long ru_oublock; /* block output operations */
long ru_msgsnd;/* messages sent */
long ru_msgrcv;/* messages received */
long ru_nsignals; /* signals received */
long ru_nvcsw; /* voluntary context switches */
long ru_nivcsw;/* involuntary context switches */
};

The fields are interpreted as follows:

ru_utime the total amount of time spent executing in user mode.
ru_stime the total amount of time spent in the system executing on behalf of the process(es).
ru_maxrss the maximum resident set size utilized (in kilobytes).
ru_ixrss an "integral" value indicating the amount of memory used by the text segment that was also shared among other processes. This value is expressed in units of kilobytes * ticks-of-execution. Ticks are statistics clock ticks. The statistics clock has a frequency of sysconf _SC_CLK_TCK ticks per second.
ru_idrss an integral value of the amount of unshared memory residing in the data segment of a process (expressed in units of kilobytes * ticks-of-execution).
ru_isrss an integral value of the amount of unshared memory residing in the stack segment of a process (expressed in units of kilobytes * ticks-of-execution).
ru_minflt the number of page faults serviced without any I/O activity; here I/O activity is avoided by "reclaiming" a page frame from the list of pages awaiting reallocation.
ru_majflt the number of page faults serviced that required I/O activity.
ru_nswap the number of times a process was "swapped" out of main memory.
ru_inblock the number of times the file system had to perform input.
ru_oublock the number of times the file system had to perform output.
ru_msgsnd the number of IPC messages sent.
ru_msgrcv the number of IPC messages received.
ru_nsignals
the number of signals delivered.
ru_nvcsw the number of times a context switch resulted due to a process voluntarily giving up the processor before its time slice was completed (usually to await availability of a resource).
ru_nivcsw the number of times a context switch resulted due to a higher priority process becoming runnable or because the current process exceeded its time slice.

NOTES

The numbers ru_inblock and ru_oublock account only for real I/O; data supplied by the caching mechanism is charged only to the first process to read or write the data.

RETURN VALUES


.Rv -std getrusage

ERRORS

The getrusage system call will fail if:
[EINVAL]
The who argument is not a valid value.
[EFAULT]
The address specified by the rusage argument is not in a valid part of the process address space.

SEE ALSO

gettimeofday(2), wait(2), clocks(7)

HISTORY

BUGS


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