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getrusage(S)


getrusage -- get information about resource utilization

Synopsis

   cc. . . -lc
   

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

int getrusage(int who, struct rusage *r_usage);

Description

The getrusage function provides measures of the resources used by the current process or its terminated and waited-for child processes.

If the value of the who argument is RUSAGE_SELF, information is returned about resources used by the current process. If the value of the who argument is RUSAGE_CHILDREN, information is returned about resources used by the terminated and waited-for children of the current process. If the child is never waited for (for instance, if the parent has SA_NOCLDWAIT set or sets SIGCHLD to SIG_IGN), the resource information for the child process is discarded and not included in the resource information provided by getrusage.

The r_usage argument is a pointer to an object of type struct rusage in which the returned information is stored.

   struct  rusage {
           struct timeval ru_utime;        /* user time used */
           struct timeval ru_stime;        /* system time used */
           long    ru_maxrss;
   #define ru_first        ru_ixrss
           long    ru_ixrss;               /* XXX: 0 */
           long    ru_idrss;               /* XXX: sum of rm_asrss */
           long    ru_isrss;               /* XXX: 0 */
           long    ru_minflt;              /* any page faults not requiring I/O */
           long    ru_majflt;              /* any page faults requiring I/O */
           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 */
   #define ru_last         ru_nivcsw
   };

The fields are interpreted as follows:


ru_utime
The total amount of time spent executing in user mode. Time is given in seconds and microseconds.

ru_stime
The total amount of time spent executing in system mode. Time is given in seconds and microseconds.

ru_maxrss
The maximum resident set size. Size is given in pages (the size of a page, in bytes, is given by the getpagesize(S) system call).

ru_ixrss
Currently returns 0.


ru_idrss
An integral value indicating the amount of memory in use by a process while the process is running. This value is the sum of the resident set sizes of the process running when a clock tick occurs. The value is given in pages times clock ticks. Note: it does not take sharing into account.


ru_isrss
Currently returns 0.

ru_minflt
The number of page faults serviced which did not require any physical I/O activity.

ru_majflt
The number of page faults serviced which required physical I/O activity. This could include page ahead operations by the kernel.

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 in servicing a read(S) request.

ru_oublock
The number of times the file system had to perform output in servicing a write(S) request.

ru_msgsnd
The number of messages sent over sockets.

ru_msgrcv
The number of messages received from sockets.

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.

Return values

If successful, the r_usage structure is filled in and 0 is returned. If the call fails, a -1 is returned and errno is set to indicate the error.

Errors

getrusage 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 portion of the process's address space.

An invalid address for the r_usage argument may result in a core dump as opposed to returning EFAULT.

See also

exit(S), getrlimit(S), gettimeofday(S), read(S), sar(ADM), sigaction(S), time(S), times(S), wait(S), write(S)

Notices

Only the timeval fields of struct rusage are supported in this implementation.

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

Standards conformance

This routine conforms to X/Open System Interfaces and Headers, Issue 4, Version 2.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003