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32 .\" @(#)gprof.1 8.1 (Berkeley) 6/6/93
40 .Nd display call graph profile data
44 .Op Ar a.out Op Ar a.out.gmon ...
47 produces an execution profile of C, Pascal, or Fortran77 programs.
48 The effect of called routines is incorporated in the profile of each caller.
49 The profile data is taken from the call graph profile file
50 which is created by programs that are compiled with the
59 option also links in versions of the library routines
60 that are compiled for profiling.
62 reads the given object file (the default is
64 and establishes the relation between it's symbol table
65 and the call graph profile. The default graph profile file name is the name
66 of the executable with the suffix
69 If more than one profile file is specified,
72 output shows the sum of the profile information in the given profile files.
75 calculates the amount of time spent in each routine.
76 Next, these times are propagated along the edges of the call graph.
77 Cycles are discovered, and calls into a cycle are made to share the time
79 The first listing shows the functions
80 sorted according to the time they represent
81 including the time of their call graph descendents.
82 Below each function entry is shown its (direct) call graph children,
83 and how their times are propagated to this function.
84 A similar display above the function shows how this function's time and the
85 time of its descendents is propagated to its (direct) call graph parents.
87 Cycles are also shown, with an entry for the cycle as a whole and
88 a listing of the members of the cycle and their contributions to the
89 time and call counts of the cycle.
91 Second, a flat profile is given,
92 similar to that provided by
94 This listing gives the total execution times, the call counts,
95 the time in msec or usec the call spent in the routine itself, and
96 the time in msec or usec the call spent in the routine itself including
99 Finally, an index of the function names is provided.
101 The following options are available:
104 Suppresses the printing of statically declared functions.
105 If this option is given, all relevant information about the static function
106 (e.g., time samples, calls to other functions, calls from other functions)
107 belongs to the function loaded just before the static function in the
111 Suppresses the printing of a description of each field in the profile.
113 The static call graph of the program is discovered by a heuristic
114 that examines the text space of the object file.
115 Static-only parents or children are shown
116 with call counts of 0.
117 This option is not supported on some architectures.
119 Find a minimal set of arcs that can be broken to eliminate all cycles with
122 Caution: the algorithm used to break cycles is exponential,
123 so using this option may cause
125 to run for a very long time.
127 Suppresses the printing of the graph profile entry for routine
129 and all its descendants
130 (unless they have other ancestors that aren't suppressed).
136 may be given with each
140 Suppresses the printing of the graph profile entry for routine
142 (and its descendants) as
144 above, and also excludes the time spent in
146 (and its descendants) from the total and percentage time computations.
154 Prints the graph profile entry of only the specified routine
162 may be given with each
166 Prints the graph profile entry of only the routine
168 and its descendants (as
170 above) and also uses only the times of the printed routines
171 in total time and percentage computations.
177 may be given with each
187 .It Fl k Ar fromname Ar toname
188 Will delete any arcs from routine
192 This can be used to break undesired cycles.
196 Only one pair of routine names may be given with each
200 Suppresses the printing of the call-graph profile.
202 Suppresses the printing of the flat profile.
206 is produced that represents
207 the sum of the profile information in all the specified profile files.
208 This summary profile file may be given to later
209 executions of gprof (probably also with a
211 to accumulate profile data across several runs of an
215 Suppresses the printing of functions whose names are not visible to
216 C programs. For the ELF object format, this means names that
219 character. For the a.out object format, it means names that do not
223 All relevant information about such functions belongs to the
224 (non-suppressed) function with the next lowest address.
225 This is useful for eliminating "functions" that are just labels
226 inside other functions.
228 Displays routines that have zero usage (as shown by call counts
229 and accumulated time).
230 This is useful with the
232 option for discovering which routines were never called.
235 .Bl -tag -width a.out.gmon -compact
237 The namelist and text space.
239 Dynamic call graph and profile.
241 Summarized dynamic call graph and profile.
250 .%T "An Execution Profiler for Modular Programs"
254 .%J "Software - Practice and Experience"
260 .%T "gprof: A Call Graph Execution Profiler"
264 .%J "Proceedings of the SIGPLAN '82 Symposium on Compiler Construction, SIGPLAN Notices"
277 The granularity of the sampling is shown, but remains
279 We assume that the time for each execution of a function
280 can be expressed by the total time for the function divided
281 by the number of times the function is called.
282 Thus the time propagated along the call graph arcs to the function's
283 parents is directly proportional to the number of times that
286 Parents that are not themselves profiled will have the time of
287 their profiled children propagated to them, but they will appear
288 to be spontaneously invoked in the call graph listing, and will
289 not have their time propagated further.
290 Similarly, signal catchers, even though profiled, will appear
291 to be spontaneous (although for more obscure reasons).
292 Any profiled children of signal catchers should have their times
293 propagated properly, unless the signal catcher was invoked during
294 the execution of the profiling routine, in which case all is lost.
296 The profiled program must call
298 or return normally for the profiling information to be saved
299 in the graph profile file.