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gprof(1)                                                              gprof(1)




NAME

       gprof - display call graph profile data


SYNOPSIS

       gprof [ options ] [ a.out [ gmon.out ... ] ]


DESCRIPTION

       gprof  produces  an execution profile of a C, Pascal, or Fortran77 pro-
       gram.  The effect of called routines is incorporated in the profile  of
       each  caller.   The  profile  data is taken from the call graph profile
       file (gmon.out by default), which is created by programs compiled  with
       the  -pg  option  of  cc,  pc,  and f77.  The symbol table in the named
       object file (a.out by default) is read and  correlated  with  the  call
       graph  profile  file.   If more than one profile file is specified, the
       gprof output shows the sum of the profile information in the given pro-
       file files.

       First, a flat profile is given.  This listing gives the total execution
       times and call counts for each of the functions in the program,  sorted
       by decreasing time.

       Next,  these  times  are  propagated along the edges of the call graph.
       Cycles are discovered, and calls into a cycle are  made  to  share  the
       time of the cycle.  A second listing shows the functions sorted accord-
       ing to the time they represent including the time of their  call  graph
       descendents.   Below  each  function  entry  is shown its (direct) call
       graph children, and how their times are propagated to this function.  A
       similar  display  above the function shows how this function's time and
       the time of its descendents is propagated to its  (direct)  call  graph
       parents.

       Cycles  are  also shown, with an entry for the cycle as a whole as well
       as a listing of the members of the cycle and their contributions to the
       time and call counts of the cycle.


UNIVERSAL FILE SUPPORT

       gprof  accepts  a ``universal'' file for the a.out file, using the host
       architecture from the file.  (It is an error if the ``universal''  file
       does not contain the host architecture.)


OPTIONS

       The following options are available:

       -a     suppresses  the displaying of statically declared functions.  If
              this option is given, all relevant information about the  static
              function  (such as time samples, calls to other functions, calls
              from other functions) belongs to the function loaded just before
              the static function in the a.out file.

       -b     suppresses  the displaying of a description of each field in the
              profile.

       -c     the static call graph of the program is discovered by a  heuris-
              tic  which  examines the text space of the object file.  Static-
              only parents or children are indicated with call  counts  of  0.
              (The -c option is currently not supported.)

       -e name
              suppresses the displaying of the graph profile entry for routine
              name and all its descendants (unless they have  other  ancestors
              that  aren't suppressed).  More than one -e option may be given.
              Only one name may be given with each -e option.

       -E name
              suppresses the displaying of the graph profile entry for routine
              name  (and  its descendants) as -e, above, and also excludes the
              time spent in name (and its descendants) from the total and per-
              centage  time  computations.  (For example, -E mcount and all of
              the other monitor(3) routines are excluded by default.)

       -f name
              displays the graph profile entry of only the  specified  routine
              name and its descendants.  More than one -f option may be given.
              Only one name may be given with each -f option.

       -F name
              displays the graph profile entry of only the  routine  name  and
              its  descendants  (as -f, above) and also uses only the times of
              the displayed routines in total  time  and  percentage  computa-
              tions.  More than one -F option may be given.  Only one name may
              be given with each -F option.  The -F option  overrides  the  -E
              option.

       -s     a  profile file gmon.sum is produced which represents the sum of
              the profile information in  all  the  specified  profile  files.
              This  summary profile file may be given to subsequent executions
              of gprof (probably also with a -s) to  accumulate  profile  data
              across several runs of an a.out file.

       -S     produces four order files suitable as input to ld(1): gmon.order
              is an ordering based on a closest is best algorithm, callf.order
              is  based  on call frequency, callo.order is based on call order
              and time.order is based on time.  The order files  contain  only
              those  functions which were called or sampled (including sponta-
              neous functions). For library functions to appear  correctly  in
              the  order  file,  a  whatsloaded  file produced by ld(1) should
              exist in the working directory. Filenames in the order file will
              be  missing  for: files compiled without the -g option, assembly
              files, and stripped executables.  This option does not work with
              executables  that  have  already been scattered.  The gmon.order
              file can take a long time to produce and can be suppressed  with
              the -x option.

       -z     displays  routines  which  have zero usage (as indicated by call
              counts and accumulated time).  This  is  useful  in  conjunction
              with  the  -c  option  for discovering which routines were never
              called.


FILES

       a.out           the namelist and text space.
       gmon.out        dynamic call graph and profile.
       gmon.sum        summarized dynamic call graph and profile.
       gmon.order      ordering based on closest is best algorithm.
       callf.order     ordering based on call frequency.
       callo.order     ordering based on call order.
       time.order      ordering based on time.


SEE ALSO

       monitor(3), profil(2), cc(1)
       dyld(1) and the DYLD_IMAGE_SUFFIX environment variable
       ``gprof: A Call Graph Execution Profiler'', by Graham,  S.L.,  Kessler,
       P.B.,  McKusick, M.K.; Proceedings of the SIGPLAN '82 Symposium on Com-
       piler Construction, SIGPLAN Notices, Vol. 17, No. 6, pp. 120-126,  June
       1982.


BUGS

       Beware  of  quantization  errors.   The  granularity of the sampling is
       shown, but remains statistical at best.  We assume that  the  time  for
       each execution of a function can be expressed by the total time for the
       function divided by the number of times the function is  called.   Thus
       the  time propagated along the call graph arcs to parents of that func-
       tion is directly proportional to the number of times that arc  is  tra-
       versed.

       Parents  which  are not themselves profiled will have the time of their
       profiled children propagated to them, but they will appear to be  spon-
       taneously  invoked  in  the call graph listing, and will not have their
       time propagated further.  Similarly, signal catchers, even though  pro-
       filed,  will  appear  to be spontaneous (although for more obscure rea-
       sons).  Any profiled children of  signal  catchers  should  have  their
       times propagated properly, unless the signal catcher was invoked during
       the execution of the profiling routine, in which case all is lost.

       The profiled program must call exit(2) or return normally for the  pro-
       filing information to be saved in the gmon.out file.



Apple Computer, Inc.             July 28, 2005                        gprof(1)

Mac OS X 10.6 - Generated Thu Sep 17 20:07:45 CDT 2009
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