Manual Pages  — GPROF

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 ‘.amp;’ 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).

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

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

The profiled program must call exit(3) or return normally for the profiling information to be saved in the graph profile file.