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18 .\" @(#)gprof.1 6.6 (Berkeley) 7/24/90
19 .\"
20 .TH GPROF 1 "January 29, 1993"
21 .SH NAME
22 gprof \- display call graph profile data
23 .SH SYNOPSIS
24 .B gprof [ \-abcsz ] [ \-e|\-E
25 .I name
26 .B ] [ \-f|\-F
27 .I name
28 .B ]
29 .B [ \-k
30 .I fromname toname
31 .B ] [
32 .I objfile
33 .B [
34 .I gmon.out
35 .B ]
36 .B ]
37 .SH DESCRIPTION
38 .B gprof
39 produces an execution profile of C, Pascal, or Fortran77 programs.
40 The effect of called routines is incorporated in the profile of each caller.
41 The profile data is taken from the call graph profile file
42 \&(`gmon.out' default) which is created by programs
43 that are compiled with the
44 .B \-pg
45 option of
46 .BR cc ( 1 ) ,
47 .BR pc ( 1 ) ,
48 and
49 .BR f77 ( 1 ) .
50 The
51 .B \-pg
52 option also links in versions of the library routines
53 that are compiled for profiling.
54 .B Gprof
55 reads the given object file (the default is `a.out')
56 and establishes the relation between its symbol table
57 and the call graph profile from `gmon.out'.
58 If more than one profile file is specified,
59 the
60 .B gprof
61 output shows the sum of the profile information in the given profile files.
62 .PP
63 .B Gprof
64 calculates the amount of time spent in each routine.
65 Next, these times are propagated along the edges of the call graph.
66 Cycles are discovered, and calls into a cycle are made to share the time
67 of the cycle.
68 The first listing shows the functions
69 sorted according to the time they represent
70 including the time of their call graph descendants.
71 Below each function entry is shown its (direct) call graph children,
72 and how their times are propagated to this function.
73 A similar display above the function shows how this function's time and the
74 time of its descendants is propagated to its (direct) call graph parents.
75 .PP
76 Cycles are also shown, with an entry for the cycle as a whole and
77 a listing of the members of the cycle and their contributions to the
78 time and call counts of the cycle.
79 .PP
80 Second, a flat profile is given,
81 similar to that provided by
82 .BR prof ( 1 ) .
83 This listing gives the total execution times, the call counts,
84 the time in milliseconds the call spent in the routine itself, and
85 the time in milliseconds the call spent in the routine itself including
86 its descendants.
87 .PP
88 Finally, an index of the function names is provided.
89 .SH OPTIONS
90 The following options are available:
91 .TP
92 .B \-a
93 suppresses the printing of statically declared functions.
94 If this option is given, all relevant information about the static function
95 (e.g., time samples, calls to other functions, calls from other functions)
96 belongs to the function loaded just before the static function in the
97 \&`objfile' file.
98 .TP
99 .B \-b
100 suppresses the printing of a description of each field in the profile.
101 .TP
102 .B \-c
103 the static call graph of the program is discovered by a heuristic
104 that examines the text space of the object file.
105 Static-only parents or children are shown
106 with call counts of 0.
107 .TP
108 .BI "\-e " name
109 suppresses the printing of the graph profile entry for routine
110 .I name
111 and all its descendants
112 (unless they have other ancestors that aren't suppressed).
113 More than one
114 .B \-e
115 option may be given.
116 Only one
117 .I name
118 may be given with each
119 .B \-e
120 option.
121 .TP
122 .BI "\-E " name
123 suppresses the printing of the graph profile entry for routine
124 .I name
125 (and its descendants) as
126 .B \-e ,
127 above, and also excludes the time spent in
128 .I name
129 (and its descendants) from the total and percentage time computations.
130 (For example,
131 .BI "\-E " mcount
132 .BI "\-E " mcleanup
133 is the default.)
134 .TP
135 .BI "\-f " name
136 prints the graph profile entry of only the specified routine
137 .I name
138 and its descendants.
139 More than one
140 .B \-f
141 option may be given.
142 Only one
143 .I name
144 may be given with each
145 .B \-f
146 option.
147 .TP
148 .BI "\-F " name
149 prints the graph profile entry of only the routine
150 .I name
151 and its descendants (as
152 .B \-f ,
153 above) and also uses only the times of the printed routines
154 in total time and percentage computations.
155 More than one
156 .B \-F
157 option may be given.
158 Only one
159 .I name
160 may be given with each
161 .B \-F
162 option.
163 The
164 .B \-F
165 option
166 overrides
167 the
168 .B \-E
169 option.
170 .TP
171 .BI "\-k " "fromname toname"
172 will delete any arcs from routine
173 .I fromname
174 to routine
175 .IR toname .
176 This can be used to break undesired cycles.
177 More than one
178 .B \-k
179 option may be given.
180 Only one pair of routine names may be given with each
181 .B \-k
182 option.
183 .TP
184 .B \-s
185 a profile file `gmon.sum' is produced that represents
186 the sum of the profile information in all the specified profile files.
187 This summary profile file may be given to later
188 executions of gprof (probably also with a
189 .BR \-s )
190 to accumulate profile data across several runs of an `objfile' file.
191 .TP
192 .B -v
193 prints the version number for gprof, and then exits.
194 .TP
195 .B -z
196 displays routines that have zero usage (as shown by call counts
197 and accumulated time).
198 This is useful with the
199 .B \-c
200 option for discovering which routines were never called.
201 .PP
202 .SH FILES
203 .ta \w'gmon.sum 'u
204 a.out the namelist and text space.
205 .br
206 gmon.out dynamic call graph and profile.
207 .br
208 gmon.sum summarized dynamic call graph and profile.
209 .SH SEE ALSO
210 .BR monitor ( 3 ) ,
211 .BR profil ( 2 ) ,
212 .BR cc ( 1 ) ,
213 .BR prof ( 1 )
214 .sp
215 ``An Execution Profiler for Modular Programs'',
216 by S. Graham, P. Kessler, M. McKusick;
217 .I
218 Software \- Practice and Experience,
219 Vol. 13, pp. 671-685, 1983.
220 .sp
221 ``gprof: A Call Graph Execution Profiler'',
222 by S. Graham, P. Kessler, M. McKusick;
223 .I
224 Proceedings of the SIGPLAN '82 Symposium on Compiler Construction,
225 SIGPLAN Notices, Vol. 17, No 6, pp. 120-126, June 1982.
226 .SH HISTORY
227 .B Gprof
228 appeared in 4.2 BSD.
229 .SH BUGS
230 The granularity of the sampling is shown, but remains
231 statistical at best.
232 We assume that the time for each execution of a function
233 can be expressed by the total time for the function divided
234 by the number of times the function is called.
235 Thus the time propagated along the call graph arcs to the function's
236 parents is directly proportional to the number of times that
237 arc is traversed.
238 .PP
239 Parents that are not themselves profiled will have the time of
240 their profiled children propagated to them, but they will appear
241 to be spontaneously invoked in the call graph listing, and will
242 not have their time propagated further.
243 Similarly, signal catchers, even though profiled, will appear
244 to be spontaneous (although for more obscure reasons).
245 Any profiled children of signal catchers should have their times
246 propagated properly, unless the signal catcher was invoked during
247 the execution of the profiling routine, in which case all is lost.
248 .PP
249 The profiled program must call
250 .BR exit ( 2 )
251 or return normally for the profiling information to be saved
252 in the `gmon.out' file.