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/resource.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 The maximum resident set size utilized (in
               kilobytes).



Printed 4/6/89                                                  1

GETRUSAGE(2)            COMMAND REFERENCE            GETRUSAGE(2)



     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 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



Printed 4/6/89                                                  2

GETRUSAGE(2)            COMMAND REFERENCE            GETRUSAGE(2)



               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) and wait(2).






























Printed 4/6/89                                                  3

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