249 lines
7.3 KiB
Groff
249 lines
7.3 KiB
Groff
.\" Copyright (c) 1983, 1990 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms are permitted provided
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.\" that: (1) source distributions retain this entire copyright notice and
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.\" comment, and (2) distributions including binaries display the following
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.\" acknowledgement: ``This product includes software developed by the
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.\" University of California, Berkeley and its contributors'' in the
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.\" documentation or other materials provided with the distribution and in
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.\" all advertising materials mentioning features or use of this software.
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.\" Neither the name of the University nor the names of its contributors may
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.\" be used to endorse or promote products derived from this software without
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.\" specific prior written permission.
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.\" @(#)gprof.1 6.6 (Berkeley) 7/24/90
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.\"
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.TH GPROF 1 "July 24, 1990"
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.SH NAME
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gprof \- display call graph profile data
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.SH SYNOPSIS
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.B gprof [ \-abcsz ] [ \-e|\-E
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.I name
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.B ] [ \-f|\-F
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.I name
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.B ]
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.B [ \-k
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.I fromname toname
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.B ] [
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.I a.out
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.B [
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.I gmon.out
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.B ]
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.B ]
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.SH DESCRIPTION
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.B gprof
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produces an execution profile of C, Pascal, or Fortran77 programs.
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The effect of called routines is incorporated in the profile of each caller.
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The profile data is taken from the call graph profile file
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\&(`gmon.out' default) which is created by programs
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that are compiled with the
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.B \-pg
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option of
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.BR cc ( 1 ) ,
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.BR pc ( 1 ) ,
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and
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.BR f77 ( 1 ) .
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The
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.B \-pg
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option also links in versions of the library routines
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that are compiled for profiling.
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.B Gprof
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reads the given object file (the default is `a.out')
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and establishes the relation between its symbol table
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and the call graph profile from `gmon.out'.
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If more than one profile file is specified,
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the
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.B gprof
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output shows the sum of the profile information in the given profile files.
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.PP
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.B Gprof
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calculates the amount of time spent in each routine.
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Next, these times are propagated along the edges of the call graph.
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Cycles are discovered, and calls into a cycle are made to share the time
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of the cycle.
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The first listing shows the functions
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sorted according to the time they represent
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including the time of their call graph descendents.
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Below each function entry is shown its (direct) call graph children,
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and how their times are propagated to this function.
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A similar display above the function shows how this function's time and the
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time of its descendents is propagated to its (direct) call graph parents.
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.PP
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Cycles are also shown, with an entry for the cycle as a whole and
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a listing of the members of the cycle and their contributions to the
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time and call counts of the cycle.
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.PP
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Second, a flat profile is given,
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similar to that provided by
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.BR prof ( 1 ) .
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This listing gives the total execution times, the call counts,
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the time in milleseconds the call spent in the routine itself, and
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the time in milleseconds the call spent in the routine itself including
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its descendents.
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.PP
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Finally, an index of the function names is provided.
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.SH OPTIONS
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The following options are available:
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.TP
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.B \-a
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suppresses the printing of statically declared functions.
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If this option is given, all relevant information about the static function
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(e.g., time samples, calls to other functions, calls from other functions)
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belongs to the function loaded just before the static function in the
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\&`a.out' file.
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.TP
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.B \-b
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suppresses the printing of a description of each field in the profile.
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.TP
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.B \-c
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the static call graph of the program is discovered by a heuristic
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that examines the text space of the object file.
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Static-only parents or children are shown
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with call counts of 0.
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.TP
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.BI "\-e " name
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suppresses the printing of the graph profile entry for routine
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.I name
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and all its descendants
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(unless they have other ancestors that aren't suppressed).
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More than one
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.B \-e
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option may be given.
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Only one
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.I name
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may be given with each
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.B \-e
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option.
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.TP
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.BI "\-E " name
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suppresses the printing of the graph profile entry for routine
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.I name
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(and its descendants) as
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.B \-e ,
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above, and also excludes the time spent in
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.I name
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(and its descendants) from the total and percentage time computations.
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(For example,
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.BI "\-E " mcount
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.BI "\-E " mcleanup
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is the default.)
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.TP
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.BI "\-f " name
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prints the graph profile entry of only the specified routine
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.I name
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and its descendants.
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More than one
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.B \-f
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option may be given.
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Only one
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.I name
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may be given with each
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.B \-f
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option.
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.TP
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.BI "\-F " name
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prints the graph profile entry of only the routine
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.I name
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and its descendants (as
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.B \-f ,
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above) and also uses only the times of the printed routines
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in total time and percentage computations.
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More than one
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.B \-F
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option may be given.
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Only one
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.I name
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may be given with each
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.B \-F
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option.
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The
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.B \-F
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option
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overrides
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the
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.B \-E
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option.
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.TP
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.BI "\-k " "fromname toname"
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will delete any arcs from routine
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.I fromname
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to routine
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.IR toname .
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This can be used to break undesired cycles.
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More than one
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.B \-k
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option may be given.
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Only one pair of routine names may be given with each
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.B \-k
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option.
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.TP
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.B \-s
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a profile file `gmon.sum' is produced that represents
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the sum of the profile information in all the specified profile files.
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This summary profile file may be given to later
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executions of gprof (probably also with a
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.BR \-s )
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to accumulate profile data across several runs of an `a.out' file.
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.TP
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.B -z
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displays routines that have zero usage (as shown by call counts
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and accumulated time).
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This is useful with the
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.B \-c
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option for discovering which routines were never called.
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.PP
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.SH FILES
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.ta \w'gmon.sum 'u
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a.out the namelist and text space.
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.br
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gmon.out dynamic call graph and profile.
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.br
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gmon.sum summarized dynamic call graph and profile.
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.SH SEE ALSO
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.BR monitor ( 3 ) ,
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.BR profil ( 2 ) ,
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.BR cc ( 1 ) ,
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.BR prof ( 1 )
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.sp
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``An Execution Profiler for Modular Programs'',
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by S. Graham, P. Kessler, M. McKusick;
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.I
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Software \- Practice and Experience,
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Vol. 13, pp. 671-685, 1983.
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.sp
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``gprof: A Call Graph Execution Profiler'',
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by S. Graham, P. Kessler, M. McKusick;
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.I
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Proceedings of the SIGPLAN '82 Symposium on Compiler Construction,
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SIGPLAN Notices, Vol. 17, No 6, pp. 120-126, June 1982.
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.SH HISTORY
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.B Gprof
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appeared in 4.2 BSD.
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.SH BUGS
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The granularity of the sampling is shown, but remains
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statistical at best.
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We assume that the time for each execution of a function
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can be expressed by the total time for the function divided
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by the number of times the function is called.
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Thus the time propagated along the call graph arcs to the function's
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parents is directly proportional to the number of times that
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arc is traversed.
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.PP
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Parents that are not themselves profiled will have the time of
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their profiled children propagated to them, but they will appear
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to be spontaneously invoked in the call graph listing, and will
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not have their time propagated further.
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Similarly, signal catchers, even though profiled, will appear
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to be spontaneous (although for more obscure reasons).
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Any profiled children of signal catchers should have their times
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propagated properly, unless the signal catcher was invoked during
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the execution of the profiling routine, in which case all is lost.
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.PP
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The profiled program must call
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.BR exit ( 2 )
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or return normally for the profiling information to be saved
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in the `gmon.out' file.
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