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32 .\" @(#)gprof.1 8.1 (Berkeley) 6/6/93
40 .Nd display call graph profile data
49 .Op Fl k Ar fromname Ar toname
50 .Op Ar a.out Op Ar a.out.gmon ...
54 utility produces an execution profile of C, Pascal, or Fortran77 programs.
55 The effect of called routines is incorporated in the profile of each caller.
56 The profile data is taken from the call graph profile file
57 which is created by programs that are compiled with the
66 option also links in versions of the library routines
67 that are compiled for profiling.
68 By convention these libraries have their name suffixed with
70 i.e. the profiled version of
74 and if you specify libraries directly to the
75 compiler or linker you can use
79 Read the given object file (the default is
81 and establishes the relation between its symbol table
82 and the call graph profile.
83 The default graph profile file name is the name
84 of the executable with the suffix
87 If more than one profile file is specified,
90 output shows the sum of the profile information in the given profile files.
94 utility calculates the amount of time spent in each routine.
95 Next, these times are propagated along the edges of the call graph.
96 Cycles are discovered, and calls into a cycle are made to share the time
98 The first listing shows the functions
99 sorted according to the time they represent
100 including the time of their call graph descendants.
101 Below each function entry is shown its (direct) call graph children,
102 and how their times are propagated to this function.
103 A similar display above the function shows how this function's time and the
104 time of its descendants is propagated to its (direct) call graph parents.
106 Cycles are also shown, with an entry for the cycle as a whole and
107 a listing of the members of the cycle and their contributions to the
108 time and call counts of the cycle.
110 Second, a flat profile is given,
111 similar to that provided by
113 This listing gives the total execution times, the call counts,
114 the time in msec or usec the call spent in the routine itself, and
115 the time in msec or usec the call spent in the routine itself including
118 Finally, an index of the function names is provided.
120 The following options are available:
121 .Bl -tag -width indent
123 Suppress the printing of statically declared functions.
124 If this option is given, all relevant information about the static function
125 (e.g., time samples, calls to other functions, calls from other functions)
126 belongs to the function loaded just before the static function in the
130 Suppress the printing of a description of each field in the profile.
132 The static call graph of the program is discovered by a heuristic
133 that examines the text space of the object file.
134 Static-only parents or children are shown
135 with call counts of 0.
136 This option is not supported on some architectures.
138 Find a minimal set of arcs that can be broken to eliminate all cycles with
141 Caution: the algorithm used to break cycles is exponential,
142 so using this option may cause
144 to run for a very long time.
146 Suppress the printing of the graph profile entry for routine
148 and all its descendants
149 (unless they have other ancestors that aren't suppressed).
155 may be given with each
159 Suppress the printing of the graph profile entry for routine
161 (and its descendants) as
163 above, and also excludes the time spent in
165 (and its descendants) from the total and percentage time computations.
173 Print the graph profile entry of only the specified routine
181 may be given with each
185 Print the graph profile entry of only the routine
187 and its descendants (as
189 above) and also uses only the times of the printed routines
190 in total time and percentage computations.
196 may be given with each
206 .It Fl k Ar fromname Ar toname
207 Will delete any arcs from routine
211 This can be used to break undesired cycles.
215 Only one pair of routine names may be given with each
219 Gather information about symbols from the currently-running kernel using the
226 argument to be ignored, and allows for symbols in
230 Suppress the printing of the call-graph profile.
232 Suppress the printing of the flat profile.
236 is produced that represents
237 the sum of the profile information in all the specified profile files.
238 This summary profile file may be given to later
239 executions of gprof (probably also with a
241 to accumulate profile data across several runs of an
245 Suppress the printing of functions whose names are not visible to
246 C programs. For the ELF object format, this means names that
249 character. For the a.out object format, it means names that do not
253 All relevant information about such functions belongs to the
254 (non-suppressed) function with the next lowest address.
255 This is useful for eliminating "functions" that are just labels
256 inside other functions.
258 Display routines that have zero usage (as shown by call counts
259 and accumulated time).
260 This is useful with the
262 option for discovering which routines were never called.
265 .Bl -tag -width a.out.gmon -compact
267 the namelist and text space
269 dynamic call graph and profile
271 summarized dynamic call graph and profile
280 .%T "An Execution Profiler for Modular Programs"
284 .%J "Software - Practice and Experience"
290 .%T "gprof: A Call Graph Execution Profiler"
294 .%J "Proceedings of the SIGPLAN '82 Symposium on Compiler Construction, SIGPLAN Notices"
307 The granularity of the sampling is shown, but remains
309 We assume that the time for each execution of a function
310 can be expressed by the total time for the function divided
311 by the number of times the function is called.
312 Thus the time propagated along the call graph arcs to the function's
313 parents is directly proportional to the number of times that
316 Parents that are not themselves profiled will have the time of
317 their profiled children propagated to them, but they will appear
318 to be spontaneously invoked in the call graph listing, and will
319 not have their time propagated further.
320 Similarly, signal catchers, even though profiled, will appear
321 to be spontaneous (although for more obscure reasons).
322 Any profiled children of signal catchers should have their times
323 propagated properly, unless the signal catcher was invoked during
324 the execution of the profiling routine, in which case all is lost.
326 The profiled program must call
328 or return normally for the profiling information to be saved
329 in the graph profile file.