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GPROF(1) GPROF(1) NAME gprof - display call graph profile data SYNOPSIS gprof [ options ] [ a.out [ gmon.out ... ] ] DESCRIPTION gprof produces an execution profile of C, Pascal, or Fortran77 pro‐ grams. The effect of called routines is incorporated in the profile of each caller. The profile data is taken from the call graph profile file (gmon.out default) which is created by programs which are compiled with the -pg option of cc, pc, and f77. That option also links in ver‐ sions of the library routines which are compiled for profiling. The symbol table in the named object file (a.out default) is read and cor‐ related with the call graph profile file. If more than one profile file is specified, the gprof output shows the sum of the profile infor‐ mation in the given profile files. First, a flat profile is given, similar to that provided by prof(1). This listing gives the total execution times and call counts for each of the functions in the program, sorted by decreasing time. Next, these times are propagated along the edges of the call graph. Cycles are discovered, and calls into a cycle are made to share the time of the cycle. A second listing shows the functions sorted accord‐ ing to the time they represent including the time of their call graph descendents. Below each function entry is shown its (direct) call graph children, and how their times are propagated to this function. A similar display above the function shows how this function’s time and the time of its descendents is propagated to its (direct) call graph parents. Cycles are also shown, with an entry for the cycle as a whole and a listing of the members of the cycle and their contributions to the time and call counts of the cycle. The following options are available: -a suppresses the printing of statically declared functions. If this option is given, all relevant information about the static function (e.g., time samples, calls to other functions, calls from other functions) belongs to the function loaded just before the static function in the a.out file. -b supresses the printing of a description of each field in the profile. -c the static call graph of the program is discovered by a heuris‐ tic which examines the text space of the object file. Static- only parents or children are indicated with call counts of 0. -e name suppresses the printing of the graph profile entry for routine name and all its descendants (unless they have other ancestors that aren’t suppressed). More than one -e option may be given. Only one name may be given with each -e option. -E name suppresses the printing of the graph profile entry for routine name (and its descendants) as -e, above, and also excludes the time spent in name (and its descendants) from the total and per‐ centage time computations. (For example, -E mcount -E mcleanup is the default.) -f name prints the graph profile entry of only the specified routine name and its descendants. More than one -f option may be given. Only one name may be given with each -f option. -F name prints the graph profile entry of only the routine name and its descendants (as -f, above) and also uses only the times of the printed routines in total time and percentage computations. More than one -F option may be given. Only one name may be given with each -F option. The -F option overrides the -E option. -s a profile file gmon.sum is produced which represents the sum of the profile information in all the specified profile files. This summary profile file may be given to subsequent executions of gprof (probably also with a -s) to accumulate profile data across several runs of an a.out file. -z displays routines which have zero usage (as indicated by call counts and accumulated time). This is useful in conjunction with the -c option for discovering which routines were never called. FILES a.out the namelist and text space. gmon.out dynamic call graph and profile. gmon.sum summarized dynamic call graph and profile. SEE ALSO monitor(3), profil(2), cc(1), prof(1) ‘‘gprof: A Call Graph Execution Profiler’’, by Graham, S.L., Kessler, P.B., McKusick, M.K.; Proceedings of the SIGPLAN 82 Symposium on Com piler Construction, SIGPLAN Notices, Vol. 17, No. 6, pp. 120-126, June 1982. BUGS Beware of quantization errors. The granularity of the sampling is shown, but remains statistical at best. We assume that the time for each execution of a function can be expressed by the total time for the function divided by the number of times the function is called. Thus the time propagated along the call graph arcs to parents of that func‐ tion is directly proportional to the number of times that arc is tra‐ versed. Parents which are not themselves profiled will have the time of their profiled children propagated to them, but they will appear to be spon‐ taneously invoked in the call graph listing, and will not have their time propagated further. Similarly, signal catchers, even though pro‐ filed, will appear to be spontaneous (although for more obscure rea‐ sons). Any profiled children of signal catchers should have their times propagated properly, unless the signal catcher was invoked during the execution of the profiling routine, in which case all is lost. The profiled program must call exit(2) or return normally for the pro‐ filing information to be saved in the gmon.out file. 4.2 Berkeley Distribution April 29, 1985 GPROF(1)
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Generated: 2016-12-26 |
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