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NAME    [Toc]    [Back]

     gprof - display call graph profile data

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

     gprof produces an execution profile of C,  Pascal,  or  Fortran77 programs.
     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  default)  which  is  created by programs that are
compiled with
     the -pg option of cc(1), pc, and f77(1).  The -pg option also links in
     versions  of the library routines that are compiled for profiling.  gprof
     reads the given object file (the default is a.out)  and  establishes the
     relation between its symbol table and the call graph profile
     gmon.out.  If more than one profile file is  specified,  the
gprof output
     shows  the  sum of the profile information in the given profile files.

     gprof calculates the amount of time spent in  each  routine.
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.
     The  first  listing  shows the functions sorted according 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 and a listing
  of  the members of the cycle and their contributions to
the time and
     call counts of the cycle.

     Second, a flat profile is given, similar to that provided by
prof.  This
     listing  gives  the  total execution times, the call counts,
the time in
     milliseconds the call spent in the routine itself,  and  the
time in milliseconds
 the call spent in the routine itself including its

     Finally, an index of the function names is provided.

     The options are as follows:

     -a      Suppresses the printing of statically declared functions.  If
             this option is given, all relevant information about
the static
             function (e.g., 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 printing of  a  description  of  each
field in the

     -c       The  static call graph of the program is discovered
by a heuristic
             that examines the text space  of  the  object  file.
             parents or children are shown with call counts of 0.

     -C count
             Find a minimal set of arcs that  can  be  broken  to
eliminate all
             cycles with count or more members.  Caution: the algorithm used
             to break cycles is exponential, so using this option
may cause
             gprof to run for a very long time.

     -e name
             Suppresses  the  printing of the graph profile entry
for routine
             name and all its descendants (unless they have other
             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 printing 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 percentage
  time computations.  (For example, -E mcount
-E mcleanup
             is the default.)

     -f name
             Prints 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
             Prints the graph profile entry of only  the  routine
name and its
             descendants  (as  -f,  above) and also uses only the
times of the
             printed routines in total time and percentage computations.  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.

     -k fromname toname
             Will  delete  any arcs from routine fromname to routine toname.
             This can be used to break  undesired  cycles.   More
than one -k option
  may  be given.  Only one pair of routine names
may be given
             with each -k option.

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

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

ENVIRONMENT    [Toc]    [Back]

     PROFDIR  Directory to place profiling information in a  file
              pid.progname.   If  it  is  set to a null value, no
profiling information
 is output.  Otherwise, profiling information
is placed in
              the file gmon.out.

FILES    [Toc]    [Back]

     a.out     namelist and text space
     gmon.out  dynamic call graph and profile
     gmon.sum  summarized dynamic call graph and profile

SEE ALSO    [Toc]    [Back]

     cc(1), profil(2), moncontrol(3)

     S.  Graham,  P. Kessler, and M. McKusick, "An Execution Profiler for
     Modular Programs", Software - Practice and  Experience,  13,
pp. 671-685,

     S. Graham, P. Kessler, and M. McKusick, "gprof: A Call Graph
     Profiler", Proceedings  of  the  SIGPLAN  '82  Symposium  on
     Construction,  SIGPLAN  Notices,  6,  17,  pp. 120-126, June

HISTORY    [Toc]    [Back]

     The gprof profiler appeared in 4.2BSD.

BUGS    [Toc]    [Back]

     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 the function's parents is directly proportional to the number
 of times that arc is traversed.

     Parents  that are not themselves profiled will have the time
of their profiled
 children propagated to them, but they will  appear  to
be spontaneously
 invoked in the call graph listing, and will not have
their time
     propagated further.  Similarly, signal catchers, even though
     will  appear  to  be  spontaneous (although for more obscure
reasons).  Any
     profiled children of signal catchers should have their times
     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(3)  or  return  normally
for the profiling
 information to be saved in the gmon.out file.

OpenBSD      3.6                           June      6,      1993
[ Back ]
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