GETRUSAGE(2) MidnightBSD System Calls Manual GETRUSAGE(2)

NAME

getrusage — get information about resource utilization

LIBRARY

Standard C Library (libc, −lc)

SYNOPSIS

#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>

#define

RUSAGE_SELF

0

#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

The getrusage() function returns the value 0 if successful; otherwise the value −1 is returned and the global variable errno is set to indicate the error.

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

The getrusage() system call appeared in 4.2BSD.

BUGS

There is no way to obtain information about a child process that has not yet terminated.

MidnightBSD 0.3 June 4, 1993 MidnightBSD 0.3