4.3BSD-UWisc/man/cat1/gprof.1
GPROF(1) UNIX Programmer's Manual GPROF(1)
NAME
gprof - display call graph profile data
SYNOPSIS
gprof [ options ] [ a.out [ gmon.out ... ] ]
DESCRIPTION
_g_p_r_o_f produces an execution profile of C, Pascal, or For-
tran77 programs. The effect of called routines is incor-
porated in the profile of each caller. The profile data is
taken from the call graph profile file (_g_m_o_n._o_u_t default)
which is created by programs which are compiled with the -pg
option of _c_c, _p_c, and _f_7_7. That option also links in ver-
sions of the library routines which are compiled for profil-
ing. The symbol table in the named object file (_a._o_u_t
default) is read and correlated with the call graph profile
file. If more than one profile file is specified, the _g_p_r_o_f
output shows the sum of the profile information in the given
profile files.
First, a flat profile is given, similar to that provided by
_p_r_o_f(1). 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 chil-
dren, 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 pro-
pagated 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.
The following options are available:
-a suppresses the printing of statically declared func-
tions. If this option is given, all relevant informa-
tion 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._o_u_t file.
-b supresses the printing of a description of each field
in the profile.
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GPROF(1) UNIX Programmer's Manual GPROF(1)
-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 _n_a_m_e
suppresses the printing of the graph profile entry for
routine _n_a_m_e and all its descendants (unless they have
other ancestors that aren't suppressed). More than one
-e option may be given. Only one _n_a_m_e may be given
with each -e option.
-E _n_a_m_e
suppresses the printing of the graph profile entry for
routine _n_a_m_e (and its descendants) as -e, above, and
also excludes the time spent in _n_a_m_e (and its descen-
dants) from the total and percentage time computations.
(For example, -E _m_c_o_u_n_t -E _m_c_l_e_a_n_u_p is the default.)
-f _n_a_m_e
prints the graph profile entry of only the specified
routine _n_a_m_e and its descendants. More than one -f
option may be given. Only one _n_a_m_e may be given with
each -f option.
-F _n_a_m_e
prints the graph profile entry of only the routine _n_a_m_e
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 _n_a_m_e may be given with each -F
option. The -F option overrides the -E option.
-s a profile file _g_m_o_n._s_u_m 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._o_u_t file.
-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._o_u_t the namelist and text space.
_g_m_o_n._o_u_t dynamic call graph and profile.
_g_m_o_n._s_u_m summarized dynamic call graph and profile.
SEE ALSO
monitor(3), profil(2), cc(1), prof(1)
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GPROF(1) UNIX Programmer's Manual GPROF(1)
``gprof: A Call Graph Execution Profiler'', by Graham, S.L.,
Kessler, P.B., McKusick, M.K.; _P_r_o_c_e_e_d_i_n_g_s _o_f _t_h_e _S_I_G_P_L_A_N
'_8_2 _S_y_m_p_o_s_i_u_m _o_n _C_o_m_p_i_l_e_r _C_o_n_s_t_r_u_c_t_i_o_n, SIGPLAN Notices,
Vol. 17, No. 6, pp. 120-126, June 1982.
BUGS
Beware of quantization errors. The granularity of the sam-
pling 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 pro-
pagated along the call graph arcs to parents of that func-
tion 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 list-
ing, and will not have their time propagated further. Simi-
larly, 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 _e_x_i_t(2) or return normally
for the profiling information to be saved in the gmon.out
file.
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