gprof/gprof.1

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  18 .\"     @(#)gprof.1     6.6 (Berkeley) 7/24/90
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  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 descendents.
  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 descendents 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 milleseconds the call spent in the routine itself, and
  85 the time in milleseconds the call spent in the routine itself including
  86 its descendents.
  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.