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32 .\" @(#)gprof.1 8.1 (Berkeley) 6/6/93
33 .\" $FreeBSD: src/usr.bin/gprof/gprof.1,v 1.12.2.8 2003/02/25 20:00:47 trhodes Exp $
40 .Nd display call graph profile data
44 .Op Ar a.out Op Ar a.out.gmon ...
48 utility produces an execution profile of C, Pascal, or Fortran77 programs.
49 The effect of called routines is incorporated in the profile of each caller.
50 The profile data is taken from the call graph profile file
51 which is created by programs that are compiled with the
60 option also links in versions of the library routines
61 that are compiled for profiling.
64 these libraries are located in
65 .Pa /usr/lib/profile ,
66 i.e. the profiled version of
69 .Pa /usr/lib/profile/libc.a .
70 .\"and if you specify libraries directly to the
71 .\"compiler or linker you can use
75 Read the given object file (the default is
77 and establishes the relation between its symbol table
78 and the call graph profile.
79 The default graph profile file name is the name
80 of the executable with the suffix
83 If more than one profile file is specified,
86 output shows the sum of the profile information in the given profile files.
90 utility calculates the amount of time spent in each routine.
91 Next, these times are propagated along the edges of the call graph.
92 Cycles are discovered, and calls into a cycle are made to share the time
94 The first listing shows the functions
95 sorted according to the time they represent
96 including the time of their call graph descendants.
97 Below each function entry is shown its (direct) call graph children,
98 and how their times are propagated to this function.
99 A similar display above the function shows how this function's time and the
100 time of its descendants is propagated to its (direct) call graph parents.
102 Cycles are also shown, with an entry for the cycle as a whole and
103 a listing of the members of the cycle and their contributions to the
104 time and call counts of the cycle.
106 Second, a flat profile is given,
107 similar to that provided by
109 This listing gives the total execution times, the call counts,
110 the time in msec or usec the call spent in the routine itself, and
111 the time in msec or usec the call spent in the routine itself including
114 Finally, an index of the function names is provided.
116 The following options are available:
117 .Bl -tag -width indent
119 Suppress the printing of statically declared functions.
120 If this option is given, all relevant information about the static function
121 (e.g., time samples, calls to other functions, calls from other functions)
122 belongs to the function loaded just before the static function in the
126 Suppress the printing of a description of each field in the profile.
128 The static call graph of the program is discovered by a heuristic
129 that examines the text space of the object file.
130 Static-only parents or children are shown
131 with call counts of 0.
132 This option is not supported on some architectures.
134 Find a minimal set of arcs that can be broken to eliminate all cycles with
137 Caution: the algorithm used to break cycles is exponential,
138 so using this option may cause
140 to run for a very long time.
142 Suppress the printing of the graph profile entry for routine
144 and all its descendants
145 (unless they have other ancestors that aren't suppressed).
151 may be given with each
155 Suppress the printing of the graph profile entry for routine
157 (and its descendants) as
159 above, and also excludes the time spent in
161 (and its descendants) from the total and percentage time computations.
169 Print the graph profile entry of only the specified routine
177 may be given with each
181 Print the graph profile entry of only the routine
183 and its descendants (as
185 above) and also uses only the times of the printed routines
186 in total time and percentage computations.
192 may be given with each
202 .It Fl k Ar fromname Ar toname
203 Will delete any arcs from routine
207 This can be used to break undesired cycles.
211 Only one pair of routine names may be given with each
215 Suppress the printing of the call-graph profile.
217 Suppress the printing of the flat profile.
221 is produced that represents
222 the sum of the profile information in all the specified profile files.
223 This summary profile file may be given to later
224 executions of gprof (probably also with a
226 to accumulate profile data across several runs of an
230 Suppress the printing of functions whose names are not visible to
231 C programs. For the ELF object format, this means names that
234 character. For the a.out object format, it means names that do not
238 All relevant information about such functions belongs to the
239 (non-suppressed) function with the next lowest address.
240 This is useful for eliminating "functions" that are just labels
241 inside other functions.
243 Display routines that have zero usage (as shown by call counts
244 and accumulated time).
245 This is useful with the
247 option for discovering which routines were never called.
250 .Bl -tag -width a.out.gmon -compact
252 The namelist and text space.
254 Dynamic call graph and profile.
256 Summarized dynamic call graph and profile.
265 .%T "An Execution Profiler for Modular Programs"
269 .%J "Software - Practice and Experience"
275 .%T "gprof: A Call Graph Execution Profiler"
279 .%J "Proceedings of the SIGPLAN '82 Symposium on Compiler Construction, SIGPLAN Notices"
292 The granularity of the sampling is shown, but remains
294 We assume that the time for each execution of a function
295 can be expressed by the total time for the function divided
296 by the number of times the function is called.
297 Thus the time propagated along the call graph arcs to the function's
298 parents is directly proportional to the number of times that
301 Parents that are not themselves profiled will have the time of
302 their profiled children propagated to them, but they will appear
303 to be spontaneously invoked in the call graph listing, and will
304 not have their time propagated further.
305 Similarly, signal catchers, even though profiled, will appear
306 to be spontaneous (although for more obscure reasons).
307 Any profiled children of signal catchers should have their times
308 propagated properly, unless the signal catcher was invoked during
309 the execution of the profiling routine, in which case all is lost.
311 The profiled program must call
313 or return normally for the profiling information to be saved
314 in the graph profile file.