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 a C, Pascal, or Fortran77 program. The effect of called rou-tines routines
tines is incorporated in the profile of each caller. The profile data is taken from the call graph
profile file (gmon.out by default), which is created by programs compiled with the -pg option of cc,
pc, and f77. The symbol table in the named object file (a.out by default) is read and correlated
with the call graph profile file. If more than one profile file is specified, the gprof output shows
the sum of the profile information in the given profile files.
First, a flat profile is given. 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
according 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 as well as a listing of the members of
the cycle and their contributions to the time and call counts of the cycle.
UNIVERSAL FILE SUPPORT
gprof accepts a ``universal'' file for the a.out file, using the host architecture from the file.
(It is an error if the ``universal'' file does not contain the host architecture.)
OPTIONS
The following options are available:
-a suppresses the displaying of statically declared functions. If this option is given, all rel-evant relevant
evant information about the static function (such as 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 suppresses the displaying of a description of each field in the profile.
-c the static call graph of the program is discovered by a heuristic which examines the text
space of the object file. Static-only parents or children are indicated with call counts of
0. (The -c option is currently not supported.)
-e name
suppresses the displaying 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 displaying 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 and all of the other monitor(3) rou-tines routines
tines are excluded by default.)
-f name
displays 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
displays the graph profile entry of only the routine name and its descendants (as -f, above)
and also uses only the times of the displayed routines in total time and percentage computa-tions. computations.
tions. 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.
-S produces four order files suitable as input to ld(1): gmon.order is an ordering based on a
closest is best algorithm, callf.order is based on call frequency, callo.order is based on
call order and time.order is based on time. The order files contain only those functions
which were called or sampled (including spontaneous functions). For library functions to
appear correctly in the order file, a whatsloaded file produced by ld(1) should exist in the
working directory. Filenames in the order file will be missing for: files compiled without the
-g option, assembly files, and stripped executables. This option does not work with executa-bles executables
bles that have already been scattered. The gmon.order file can take a long time to produce
and can be suppressed with the -x option.
-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.
gmon.order ordering based on closest is best algorithm.
callf.order ordering based on call frequency.
callo.order ordering based on call order.
time.order ordering based on time.
SEE ALSO
monitor(3), profil(2), cc(1)
dyld(1) and the DYLD_IMAGE_SUFFIX environment variable
``gprof: A Call Graph Execution Profiler'', by Graham, S.L., Kessler, P.B., McKusick, M.K.; Proceed-ings Proceedings
ings of the SIGPLAN '82 Symposium on Compiler 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 function is directly proportional to the number of times
that arc is traversed.
Parents which 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(2) or return normally for the profiling information to be saved
in the gmon.out file.
Apple Computer, Inc. July 28, 2005 GPROF(1)
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