GPROF
Section: User Commands (1)
Updated: 22 April 1986
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NAME
gprof - display call-graph profile data
SYNOPSIS
gprof
[
-a
] [
-b
] [
-c
] [
-e
name
] [
-E
name
]
[
-f
name
] [
-F
name
] [
-s
] [
-z
]
[
object-file
[
profile-file
... ] ]
DESCRIPTION
Gprof
produces an execution profile of C, Pascal, or
FORTRAN
77 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
(gmon.out
default) which is created by programs compiled with the
-pg
option of
cc,
pc,
and
f77.
That option also links in versions of the library routines
which are compiled for profiling. 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, execution times for each routines 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.
Next, a flat profile is given, similar to that provided by
prof(1).
This listing gives the total execution times and call counts for each of
the functions in the program, sorted by decreasing time.
Finally, an index showing the correspondence between function
names and call-graph profile index numbers.
Beware of quantization errors. The granularity of the sampling is
shown, but remains statistical at best. It is assumed 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.
The profiled program must call
exit(2)
or return normally for the profiling information to be saved in the
gmon.out
file.
OPTIONS
- -a
-
suppress printing statically declared functions. If this
option is given, all relevant information about the static function (for
instance, 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
-
Brief. Suppress descriptions 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.
- -e name
-
suppress printing 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 printing the graph profile entry for routine
name
(and its descendants) as
-e,
above, and also exclude the time spent in
name
(and its descendants) from the total and percentage time computations.
More than one
-E
option may be given. For example,
-E
mcount
-E
mcleanup
is the default.
- -f name
-
print the graph profile entry only for 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 only for routine
name
and its descendants (as
-f,
above) and also use 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.
- -s
-
produce a profile file
gmon.sum
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)
option to accumulate profile data across several runs of an
a.out
file.
- -z
-
display 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
SEE ALSO
monitor(3), profil(2), cc(1), prof(1)
Graham, S.L., Kessler, P.B., McKusick, M.K.,
`gprof: A Call Graph Execution Profiler',
Proceedings of the SIGPLAN '82 Symposium on Compiler Construction,
SIGPLAN Notices, Vol. 17, No. 6, pp. 120-126, June 1982.
BUGS
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.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- FILES
-
- SEE ALSO
-
- BUGS
-
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