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 pro-
gram. 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 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 pro-
file 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 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 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 relevant 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 heuris-
tic 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 per-
centage time computations. (For example, -E mcount and all of
the other monitor(3) routines 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. 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 sponta-
neous 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
executables 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.; 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.
Apple Computer, Inc. July 28, 2005 gprof(1)
Mac OS X 10.6 - Generated Thu Sep 17 20:07:45 CDT 2009