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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
     Fortran77 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
     versions of the library routines that are compiled for profiling.  By
     convention these libraries have their name suffixed with _p, i.e., the
     profiled 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
     descendants.  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 descendants 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.

     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
     that the call spent in the routine itself, and the time that the call
     spent in the routine itself including its descendants.  The units for the
     per-call times are normally milliseconds, but they are nanoseconds if the
     profiling clock frequency is 10 million or larger, and if a function
     appears to be never called then its total self time is printed as a
     percentage in the self time per call column.  The very high profiling
     clock frequencies needed to get sufficient accuracy in the per-call times
     for short-lived programs are only implemented for ``high resolution''
     (non-statistical) kernel profiling.

     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
             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      Suppress the printing of a description of each field in the
             profile.

     -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
             are not 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
             kernel 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
             several 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
             eliminating "functions" that are just labels inside other
             functions.

     -z      Display routines that have zero usage (as shown by call counts
             and accumulated time).

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
     number of times that arc is traversed.

     Parents that are not themselves profiled will have the time of their
     profiled children propagated to them, but they will appear to be
     spontaneously 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
     profiling information to be saved in the graph profile file.

FreeBSD 11.0-PRERELEASE        December 25, 2008       FreeBSD 11.0-PRERELEASE

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

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