getrusage(2) — UTek W2.3



GETRUSAGE(2)            COMMAND REFERENCE            GETRUSAGE(2)



NAME
     getrusage - get information about resource utilization

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

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

DESCRIPTION
     Getrusage returns information describing the resources
     utilized by the current process, or all its terminated child
     processes.  The who parameter is one of RUSAGE_SELF and
     RUSAGE_CHILDREN, defined in <sys/resouce.h>:

          #define   RUSAGE_SELF         0    /* calling process */
          #define   RUSAGE_CHILDREN     -1   /* terminated child processes */

     The buffer pointed to by rusage will be filled in with the
     following structure, defined in <sys/resource.h>:

     struct    rusage {
          struct timeval ru_utime; /* user time used */
          struct timeval ru_stime; /* system time used */
          long ru_maxrss;
          long ru_ixrss;         /* integral shared 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



Printed 10/17/86                                                1



GETRUSAGE(2)            COMMAND REFERENCE            GETRUSAGE(2)



         the maximum resident set size utilized (in kilobytes).

     ru_ixrss
         an "integral" value indicating the amount of memory used
         which was also shared among other processes.  This value
         is expressed in units of kilobytes * seconds-of-
         execution and is calculated by summing the number of
         shared memory pages in use each time the internal system
         clock ticks and then averaging over 1 second intervals.

     ru_idrss
         an integral value of the amount of unshared memory
         residing in the data segment of a process (expressed in
         units of kilobytes * seconds-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 * seconds-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 which 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_outblock
         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



Printed 10/17/86                                                2



GETRUSAGE(2)            COMMAND REFERENCE            GETRUSAGE(2)



         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.

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

DIAGNOSTICS
     Getrusage will fail if one or more of the following is true:

     [EINVAL]
         The who argument is an invalid value.

     [EFAULT]
         The argument rusage refers to an invalid address.

RETURN VALUE
     Upon successful completion, a value of 0 is returned.
     Otherwise, a value of -1 is returned and errno is set to
     indicate the error.

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

SEE ALSO
     gettimeofday(2), wait(2).






















Printed 10/17/86                                                3

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