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GETRUSAGE(2)                BSD System Calls Manual               GETRUSAGE(2)

NAME
     getrusage -- get information about resource utilization

SYNOPSIS
     #include <sys/resource.h>

     #define   RUSAGE_SELF     0
     #define   RUSAGE_CHILDREN     -1

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

DESCRIPTION
     Getrusage() returns information describing the resources utilized by the current process, or all its
     terminated child processes.  The who parameter is either RUSAGE_SELF or RUSAGE_CHILDREN.  The buffer to
     which r_usage 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 bytes).

     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-ofexecution.
                  execution.

     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:

     [EFAULT]           The address specified by the r_usage parameter is not in a valid part of the process
                        address space.

     [EINVAL]           The who parameter is not a valid value.

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

     The include file <sys/time.h> is necessary.

SEE ALSO
     gettimeofday(2), wait(2), compat(5)

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

HISTORY
     The getrusage() function call appeared in 4.2BSD.

4th Berkeley Distribution        June 4, 1993        4th Berkeley Distribution