gprof/gprof.1

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  18 .\"     @(#)gprof.1     6.6 (Berkeley) 7/24/90
  19 .\"
  20 .Dd July 24, 1990
  21 .Dt GPROF 1
  22 .Os BSD 4.2
  23 .Sh NAME
  24 .Nm gprof
  25 .Nd display call graph profile data
  26 .Sh SYNOPSIS
  27 .Nm gprof
  28 .Op options
  29 .Op Ar a.out Op Ar gmon.out ...
  30 .Sh DESCRIPTION
  31 .Nm gprof
  32 produces an execution profile of C, Pascal, or Fortran77 programs.
  33 The effect of called routines is incorporated in the profile of each caller.
  34 The profile data is taken from the call graph profile file
  35 .Pf \&( Pa gmon.out
  36 default) which is created by programs
  37 that are compiled with the
  38 .Fl pg
  39 option of
  40 .Xr cc 1 ,
  41 .Xr pc 1 ,
  42 and
  43 .Xr f77 1 .
  44 The
  45 .Fl pg
  46 option also links in versions of the library routines
  47 that are compiled for profiling.
  48 .Nm Gprof
  49 reads the given object file (the default is
  50 .Pa a.out)
  51 and establishes the relation between it's symbol table
  52 and the call graph profile from
  53 .Pa gmon.out .
  54 If more than one profile file is specified,
  55 the
  56 .Nm gprof
  57 output shows the sum of the profile information in the given profile files.
  58 .Pp
  59 .Nm Gprof
  60 calculates the amount of time spent in each routine.
  61 Next, these times are propagated along the edges of the call graph.
  62 Cycles are discovered, and calls into a cycle are made to share the time
  63 of the cycle.
  64 The first listing shows the functions
  65 sorted according to the time they represent
  66 including the time of their call graph descendents.
  67 Below each function entry is shown its (direct) call graph children,
  68 and how their times are propagated to this function.
  69 A similar display above the function shows how this function's time and the
  70 time of its descendents is propagated to its (direct) call graph parents.
  71 .Pp
  72 Cycles are also shown, with an entry for the cycle as a whole and
  73 a listing of the members of the cycle and their contributions to the
  74 time and call counts of the cycle.
  75 .Pp
  76 Second, a flat profile is given,
  77 similar to that provided by
  78 .Xr prof  1  .
  79 This listing gives the total execution times, the call counts,
  80 the time in milleseconds the call spent in the routine itself, and
  81 the time in milleseconds the call spent in the routine itself including
  82 its descendents.
  83 .Pp
  84 Finally, an index of the function names is provided.
  85 .Pp
  86 The following options are available:
  87 .Tw Fl
  88 .Tp Fl a
  89 suppresses the printing of statically declared functions.
  90 If this option is given, all relevant information about the static function
  91 (e.g., time samples, calls to other functions, calls from other functions)
  92 belongs to the function loaded just before the static function in the
  93 .Pa a.out
  94 file.
  95 .Tp Fl b
  96 suppresses the printing of a description of each field in the profile.
  97 .Tp Fl c
  98 the static call graph of the program is discovered by a heuristic
  99 that examines the text space of the object file.
 100 Static-only parents or children are shown
 101 with call counts of 0.
 102 .Tc Fl e
 103 .Ws
 104 .Ar name
 105 .Cx
 106 suppresses the printing of the graph profile entry for routine
 107 .Ar name
 108 and all its descendants
 109 (unless they have other ancestors that aren't suppressed).
 110 More than one
 111 .Fl e
 112 option may be given.
 113 Only one
 114 .Ar name
 115 may be given with each
 116 .Fl e
 117 option.
 118 .Tc Fl E
 119 .Ws
 120 .Ar name
 121 .Cx
 122 suppresses the printing of the graph profile entry for routine
 123 .Ar name
 124 (and its descendants) as
 125 .Fl e  ,
 126 above, and also excludes the time spent in
 127 .Ar name
 128 (and its descendants) from the total and percentage time computations.
 129 (For example,
 130 .Fl E
 131 .Ar mcount
 132 .Fl E
 133 .Ar mcleanup
 134 is the default.)
 135 .Tc Fl f
 136 .Ws
 137 .Ar name
 138 .Cx
 139 prints the graph profile entry of only the specified routine
 140 .Ar name
 141 and its descendants.
 142 More than one
 143 .Fl f
 144 option may be given.
 145 Only one
 146 .Ar name
 147 may be given with each
 148 .Fl f
 149 option.
 150 .Tc Fl F
 151 .Ws
 152 .Ar name
 153 .Cx
 154 prints the graph profile entry of only the routine
 155 .Ar name
 156 and its descendants (as
 157 .Fl f ,
 158 above) and also uses only the times of the printed routines
 159 in total time and percentage computations.
 160 More than one
 161 .Fl F
 162 option may be given.
 163 Only one
 164 .Ar name
 165 may be given with each
 166 .Fl F
 167 option.
 168 The
 169 .Fl F
 170 option
 171 overrides
 172 the
 173 .Fl E
 174 option.
 175 .Tc Fl k
 176 .Ws
 177 .Ar fromname
 178 .Ws
 179 .Ar toname
 180 .Cx
 181 will delete any arcs from routine
 182 .Ar fromname
 183 to routine
 184 .Ar toname  .
 185 This can be used to break undesired cycles.
 186 More than one
 187 .Fl k
 188 option may be given.
 189 Only one pair of routine names may be given with each
 190 .Fl k
 191 option.
 192 .Tp Fl s
 193 a profile file
 194 .Pa gmon.sum
 195 is produced that represents
 196 the sum of the profile information in all the specified profile files.
 197 This summary profile file may be given to later
 198 executions of gprof (probably also with a
 199 .Fl s  )
 200 to accumulate profile data across several runs of an
 201 .Pa a.out
 202 file.
 203 .Tp Fl z
 204 displays routines that have zero usage (as shown by call counts
 205 and accumulated time).
 206 This is useful with the
 207 .Fl c
 208 option for discovering which routines were never called.
 209 .Tp
 210 .Sh FILES
 211 .Dw gmon.sum
 212 .Di L
 213 .Dp Pa a.out
 214 the namelist and text space.
 215 .Dp Pa gmon.out
 216 dynamic call graph and profile.
 217 .Dp Pa gmon.sum
 218 summarized dynamic call graph and profile.
 219 .Dp
 220 .Sh SEE ALSO
 221 .Xr monitor 3 ,
 222 .Xr profil 2 ,
 223 .Xr cc 1 ,
 224 .Xr prof 1
 225 .br
 226 .Em An Execution Profiler for Modular Programs ,
 227 by
 228 S. Graham, P. Kessler, M. McKusick;
 229 Software  - Practice and Experience,
 230 Vol. 13, pp. 671-685, 1983.
 231 .br
 232 .Em gprof: A Call Graph Execution Profiler ,
 233 by S. Graham, P. Kessler, M. McKusick;
 234 Proceedings of the SIGPLAN '82 Symposium on Compiler Construction,
 235 SIGPLAN Notices, Vol. 17, No  6, pp. 120-126, June 1982.
 236 .Sh HISTORY
 237 .Nm Gprof
 238 appeared in 4.2 BSD.
 239 .Sh BUGS
 240 The granularity of the sampling is shown, but remains
 241 statistical at best.
 242 We assume that the time for each execution of a function
 243 can be expressed by the total time for the function divided
 244 by the number of times the function is called.
 245 Thus the time propagated along the call graph arcs to the function's
 246 parents is directly proportional to the number of times that
 247 arc is traversed.
 248 .Pp
 249 Parents that are not themselves profiled will have the time of
 250 their profiled children propagated to them, but they will appear
 251 to be spontaneously invoked in the call graph listing, and will
 252 not have their time propagated further.
 253 Similarly, signal catchers, even though profiled, will appear
 254 to be spontaneous (although for more obscure reasons).
 255 Any profiled children of signal catchers should have their times
 256 propagated properly, unless the signal catcher was invoked during
 257 the execution of the profiling routine, in which case all is lost.
 258 .Pp
 259 The profiled program must call
 260 .Xr exit  2
 261 or return normally for the profiling information to be saved
 262 in the
 263 .Pa gmon.out
 264 file.