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32 .\" @(#)gprof.1 8.1 (Berkeley) 6/6/93
39 .Nd display call graph profile data
43 .Op Ar a.out Op Ar a.out.gmon ...
46 produces an execution profile of C, Pascal, or Fortran77 programs.
47 The effect of called routines is incorporated in the profile of each caller.
48 The profile data is taken from the call graph profile file
49 which is created by programs that are compiled with the
58 option also links in versions of the library routines
59 that are compiled for profiling.
61 reads the given object file (the default is
63 and establishes the relation between it's symbol table
64 and the call graph profile. The default graph profile file name is the name
65 of the executable with the suffix
68 If more than one profile file is specified,
71 output shows the sum of the profile information in the given profile files.
74 calculates the amount of time spent in each routine.
75 Next, these times are propagated along the edges of the call graph.
76 Cycles are discovered, and calls into a cycle are made to share the time
78 The first listing shows the functions
79 sorted according to the time they represent
80 including the time of their call graph descendents.
81 Below each function entry is shown its (direct) call graph children,
82 and how their times are propagated to this function.
83 A similar display above the function shows how this function's time and the
84 time of its descendents is propagated to its (direct) call graph parents.
86 Cycles are also shown, with an entry for the cycle as a whole and
87 a listing of the members of the cycle and their contributions to the
88 time and call counts of the cycle.
90 Second, a flat profile is given,
91 similar to that provided by
93 This listing gives the total execution times, the call counts,
94 the time in msec or usec the call spent in the routine itself, and
95 the time in msec or usec the call spent in the routine itself including
98 Finally, an index of the function names is provided.
100 The following options are available:
103 Suppresses the printing of statically declared functions.
104 If this option is given, all relevant information about the static function
105 (e.g., time samples, calls to other functions, calls from other functions)
106 belongs to the function loaded just before the static function in the
110 Suppresses the printing of a description of each field in the profile.
112 The static call graph of the program is discovered by a heuristic
113 that examines the text space of the object file.
114 Static-only parents or children are shown
115 with call counts of 0.
116 This option is not supported on some architectures.
118 Find a minimal set of arcs that can be broken to eliminate all cycles with
121 Caution: the algorithm used to break cycles is exponential,
122 so using this option may cause
124 to run for a very long time.
126 Suppresses the printing of the graph profile entry for routine
128 and all its descendants
129 (unless they have other ancestors that aren't suppressed).
135 may be given with each
139 Suppresses the printing of the graph profile entry for routine
141 (and its descendants) as
143 above, and also excludes the time spent in
145 (and its descendants) from the total and percentage time computations.
153 Prints the graph profile entry of only the specified routine
161 may be given with each
165 Prints the graph profile entry of only the routine
167 and its descendants (as
169 above) and also uses only the times of the printed routines
170 in total time and percentage computations.
176 may be given with each
186 .It Fl k Ar fromname Ar toname
187 Will delete any arcs from routine
191 This can be used to break undesired cycles.
195 Only one pair of routine names may be given with each
199 Suppresses the printing of the call-graph profile.
201 Suppresses the printing of the flat profile.
205 is produced that represents
206 the sum of the profile information in all the specified profile files.
207 This summary profile file may be given to later
208 executions of gprof (probably also with a
210 to accumulate profile data across several runs of an
214 Suppresses the printing of functions whose names are not visible to
215 C programs. For the ELF object format, this means names that
218 character. For the a.out object format, it means names that do not
222 All relevant information about such functions belongs to the
223 (non-suppressed) function with the next lowest address.
224 This is useful for eliminating "functions" that are just labels
225 inside other functions.
227 Displays routines that have zero usage (as shown by call counts
228 and accumulated time).
229 This is useful with the
231 option for discovering which routines were never called.
234 .Bl -tag -width a.out.gmon -compact
236 The namelist and text space.
238 Dynamic call graph and profile.
240 Summarized dynamic call graph and profile.
249 .%T "An Execution Profiler for Modular Programs"
253 .%J "Software - Practice and Experience"
259 .%T "gprof: A Call Graph Execution Profiler"
263 .%J "Proceedings of the SIGPLAN '82 Symposium on Compiler Construction, SIGPLAN Notices"
276 The granularity of the sampling is shown, but remains
278 We assume that the time for each execution of a function
279 can be expressed by the total time for the function divided
280 by the number of times the function is called.
281 Thus the time propagated along the call graph arcs to the function's
282 parents is directly proportional to the number of times that
285 Parents that are not themselves profiled will have the time of
286 their profiled children propagated to them, but they will appear
287 to be spontaneously invoked in the call graph listing, and will
288 not have their time propagated further.
289 Similarly, signal catchers, even though profiled, will appear
290 to be spontaneous (although for more obscure reasons).
291 Any profiled children of signal catchers should have their times
292 propagated properly, unless the signal catcher was invoked during
293 the execution of the profiling routine, in which case all is lost.
295 The profiled program must call
297 or return normally for the profiling information to be saved
298 in the graph profile file.