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man:vtimes

GETRUSAGE(2) Linux Programmer's Manual GETRUSAGE(2)

NAME

     getrusage - get resource usage

SYNOPSIS

     #include <sys/time.h>
     #include <sys/resource.h>
     int getrusage(int who, struct rusage *usage);

DESCRIPTION

     getrusage()  returns  resource usage measures for who, which can be one
     of the following:
     RUSAGE_SELF
            Return resource usage statistics for the calling process,  which
            is the sum of resources used by all threads in the process.
     RUSAGE_CHILDREN
            Return resource usage statistics for all children of the calling
            process that have terminated and been waited for.  These statis-
            tics  will include the resources used by grandchildren, and fur-
            ther removed descendants, if all of the intervening  descendants
            waited on their terminated children.
     RUSAGE_THREAD (since Linux 2.6.26)
            Return  resource  usage  statistics for the calling thread.  The
            _GNU_SOURCE feature test macro must be defined (before including
            any  header file) in order to obtain the definition of this con-
            stant from <sys/resource.h>.
     The resource usages are returned in the structure pointed to by  usage,
     which has the following form:
         struct rusage {
             struct timeval ru_utime; /* user CPU time used */
             struct timeval ru_stime; /* system CPU time used */
             long   ru_maxrss;        /* maximum resident set size */
             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 (soft page faults) */
             long   ru_majflt;        /* page faults (hard page faults) */
             long   ru_nswap;         /* swaps */
             long   ru_inblock;       /* block input operations */
             long   ru_oublock;       /* block output operations */
             long   ru_msgsnd;        /* IPC messages sent */
             long   ru_msgrcv;        /* IPC messages received */
             long   ru_nsignals;      /* signals received */
             long   ru_nvcsw;         /* voluntary context switches */
             long   ru_nivcsw;        /* involuntary context switches */ };
     Not all fields are completed; unmaintained fields are set  to  zero  by
     the  kernel.   (The  unmaintained fields are provided for compatibility
     with other systems, and because  they  may  one  day  be  supported  on
     Linux.)  The fields are interpreted as follows:
     ru_utime
            This  is  the total amount of time spent executing in user mode,
            expressed in a timeval structure (seconds plus microseconds).
     ru_stime
            This is the total amount of time spent executing in kernel mode,
            expressed in a timeval structure (seconds plus microseconds).
     ru_maxrss (since Linux 2.6.32)
            This  is the maximum resident set size used (in kilobytes).  For
            RUSAGE_CHILDREN, this is the resident set size  of  the  largest
            child, not the maximum resident set size of the process tree.
     ru_ixrss (unmaintained)
            This field is currently unused on Linux.
     ru_idrss (unmaintained)
            This field is currently unused on Linux.
     ru_isrss (unmaintained)
            This field is currently unused on Linux.
     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 (unmaintained)
            This field is currently unused on Linux.
     ru_inblock (since Linux 2.6.22)
            The number of times the filesystem had to perform input.
     ru_oublock (since Linux 2.6.22)
            The number of times the filesystem had to perform output.
     ru_msgsnd (unmaintained)
            This field is currently unused on Linux.
     ru_msgrcv (unmaintained)
            This field is currently unused on Linux.
     ru_nsignals (unmaintained)
            This field is currently unused on Linux.
     ru_nvcsw (since Linux 2.6)
            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 (since Linux 2.6)
            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 VALUE

     On  success,  zero is returned.  On error, -1 is returned, and errno is
     set appropriately.

ERRORS

     EFAULT usage points outside the accessible address space.
     EINVAL who is invalid.

ATTRIBUTES

     For  an  explanation  of  the  terms  used   in   this   section,   see
     attributes(7).
     allbox;  lb  lb  lb  l  l  l.  Interface Attribute Value T{ getrusage()
     T}   Thread safety  MT-Safe

CONFORMING TO

     POSIX.1-2001,   POSIX.1-2008,   SVr4,   4.3BSD.    POSIX.1    specifies
     getrusage(), but specifies only the fields ru_utime and ru_stime.
     RUSAGE_THREAD is Linux-specific.

NOTES

     Resource usage metrics are preserved across an execve(2).
     Including <sys/time.h> is not required these days, but increases porta-
     bility.  (Indeed, struct timeval is defined in <sys/time.h>.)
     In Linux kernel versions before 2.6.9, if the disposition of SIGCHLD is
     set to SIG_IGN then the resource usages of child processes are automat-
     ically included in the  value  returned  by  RUSAGE_CHILDREN,  although
     POSIX.1-2001  explicitly prohibits this.  This nonconformance is recti-
     fied in Linux 2.6.9 and later.
     The structure definition shown at the start of this page was taken from
     4.3BSD Reno.
     Ancient  systems provided a vtimes() function with a similar purpose to
     getrusage().  For backward compatibility, glibc also provides vtimes().
     All new applications should be written using getrusage().
     See also the description of /proc/[pid]/stat in proc(5).

SEE ALSO

     clock_gettime(2), getrlimit(2), times(2), wait(2), wait4(2), clock(3)

COLOPHON

     This  page  is  part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs,  and  the
     latest     version     of     this    page,    can    be    found    at
     https://www.kernel.org/doc/man-pages/.

Linux 2017-09-15 GETRUSAGE(2)

/data/webs/external/dokuwiki/data/pages/man/vtimes.txt · Last modified: 2019/05/17 09:47 by 127.0.0.1

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