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GPROF(1)		FreeBSD	General	Commands Manual		      GPROF(1)

NAME
     gprof -- display call graph profile data

SYNOPSIS
     gprof [-abKlLsuz] [-C count] [-e name] [-E	name] [-f name]	[-F name]
	   [-k fromname	toname]	[a.out [a.out.gmon ...]]

DESCRIPTION
     The gprof utility produces	an execution profile of	C, Pascal, or For-
     tran77 programs.  The effect of called routines is	incorporated in	the
     profile of	each caller.  The profile data is taken	from the call graph
     profile file which	is created by programs that are	compiled with the -pg
     option of cc(1), pc(1), and f77(1).  The -pg option also links in ver-
     sions of the library routines that	are compiled for profiling.  By	con-
     vention these libraries have their	name suffixed with _p, i.e., the pro-
     filed version of libc.a is	libc_p.a and if	you specify libraries directly
     to	the compiler or	linker you can use -lc_p instead of -lc.  Read the
     given object file (the default is a.out) and establishes the relation
     between its symbol	table and the call graph profile.  The default graph
     profile file name is the name of the executable with the suffix .gmon
     appended.	If more	than one profile file is specified, the	gprof output
     shows the sum of the profile information in the given profile files.

     The gprof utility calculates the amount of	time spent in each routine.
     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.  The	first listing shows the	functions sorted according to
     the time they represent including the time	of their call graph descen-
     dants.  Below each	function entry is shown	its (direct) call graph	chil-
     dren, 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 descendants is	propagated to its (direct) call	graph parents.

     Cycles are	also shown, with an entry for the cycle	as a whole and a list-
     ing of the	members	of the cycle and their contributions to	the time and
     call counts of the	cycle.

     Second, a flat profile is given, similar to that provided by prof(1).
     This listing gives	the total execution times, the call counts, the	time
     in	msec or	usec the call spent in the routine itself, and the time	in
     msec or usec the call spent in the	routine	itself including its descen-
     dants.

     Finally, an index of the function names is	provided.

     The following options are available:

     -a	     Suppress the printing of statically declared functions.  If this
	     option is given, all relevant information about the static	func-
	     tion (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	     Suppress the printing of a	description of each field in the pro-
	     file.

     -C	count
	     Find a minimal set	of arcs	that can be broken to eliminate	all
	     cycles with count or more members.	 Caution: the algorithm	used
	     to	break cycles is	exponential, so	using this option may cause
	     gprof to run for a	very long time.

     -e	name
	     Suppress 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
	     Suppress 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 percentage
	     time computations.	 (For example, -E mcount -E mcleanup is	the
	     default.)

     -f	name
	     Print 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
	     Print 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.

     -k	fromname toname
	     Will delete any arcs from routine fromname	to routine toname.
	     This can be used to break undesired cycles.  More than one	-k
	     option may	be given.  Only	one pair of routine names may be given
	     with each -k option.

     -K	     Gather information	about symbols from the currently-running ker-
	     nel using the sysctl(3) and kldsym(2) interfaces.	This forces
	     the a.out argument	to be ignored, and allows for symbols in
	     kld(4) modules to be used.

     -l	     Suppress the printing of the call-graph profile.

     -L	     Suppress the printing of the flat profile.

     -s	     A profile file gmon.sum is	produced that represents the sum of
	     the profile information in	all the	specified profile files.  This
	     summary profile file may be given to later	executions of gprof
	     (probably also with a -s) to accumulate profile data across sev-
	     eral runs of an a.out file.

     -u	     Suppress the printing of functions	whose names are	not visible to
	     C programs.  For the ELF object format, this means	names that
	     contain the `.' character.	 For the a.out object format, it means
	     names that	do not begin with a `_'	character.  All	relevant
	     information about such functions belongs to the (non-suppressed)
	     function with the next lowest address.  This is useful for	elimi-
	     nating "functions"	that are just labels inside other functions.

     -z	     Display routines that have	zero usage (as shown by	call counts
	     and accumulated time).  This is useful with the -c	option for
	     discovering which routines	were never called.

FILES
     a.out	 The namelist and text space.
     a.out.gmon	 Dynamic call graph and	profile.
     gmon.sum	 Summarized dynamic call graph and profile.

SEE ALSO
     cc(1), profil(2), clocks(7)

     S.	Graham,	P. Kessler, and	M. McKusick, "An Execution Profiler for
     Modular Programs",	Software - Practice and	Experience, 13,	pp. 671-685,
     1983.

     S.	Graham,	P. Kessler, and	M. McKusick, "gprof: A Call Graph Execution
     Profiler",	Proceedings of the SIGPLAN '82 Symposium on Compiler
     Construction, SIGPLAN Notices, 6, 17, pp. 120-126,	June 1982.

HISTORY
     The gprof profiler	appeared in 4.2BSD.

BUGS
     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 the function's parents is directly proportional to the num-
     ber of times that arc is traversed.

     Parents that are not themselves profiled will have	the time of their pro-
     filed children propagated to them,	but they will appear to	be sponta-
     neously invoked in	the call graph listing,	and will not have their	time
     propagated	further.  Similarly, signal catchers, even though profiled,
     will appear to be spontaneous (although for more obscure reasons).	 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(3) or return normally for the profil-
     ing information to	be saved in the	graph profile file.

FreeBSD	10.1			 June 20, 2004			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | HISTORY | BUGS

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