Excluding a function from gprof results - c

Question

I want to exclude some functions from the output generated by gprof. In other words, I do not want them to be included when calculating percentage time spent by each function during execution. I read at one place -E option can be used.
However I'm using gprof -E function_to_be_exluded my_program_name, but nothing happens. The manual says it is depreciated and you should use symspecs instead. However, I have wasted half an hour trying to figure out how to achieve it with symspecs, but no luck. Anyone can kindly help me in this.

Answer 1

Exactly, gprof -e -E are deprecated and superseded by usage of newer relevant options that have argument - symspecs. So try using:
gprof --no-time=symspec
The -n option causes "gprof", in its call graph analysis, not to propagate times for
symbols matching symspec.
e.g.
gprof --no-time=name_of_function_you_dont_want_to_profile.
Use this along with your other gprof options (-E -e definitely ruled out)

Answer 2

According to the man:
for display flat profile and exclude function from it you need use -P option:
gprof main gmon.out -Pfunction_name
for display call graph and exclude function from it you need use -Q option:
gprof main gmon.out -Qfunction_name
This options can be repeated and used in the same time:
gprof main gmon.out -Pfunction_name -Qfunction_name -Qother_function_name
If you need exclude function from one report but not exclude any function from other you need use -p or -q options.
Example:
Create program:
#include <stdio.h>
#include <stdlib.h>
void func_a () {printf ("%s ",__FUNCTION__);}
void func_b () {printf ("%s ",__FUNCTION__);}
void func_c () {printf ("%s ",__FUNCTION__);}
int main ()
{
func_a ();
func_b ();
func_c ();
return EXIT_SUCCESS;
}
Compile it:
gcc main.c -pg -o main
And launch:
$ ./main
func_a func_b func_c
Generate profile reports:
If you need print only flat profile you need call:
$ gprof main gmon.out -b -p
% cumulative self self total
time seconds seconds calls Ts/call Ts/call name
0.00 0.00 0.00 1 0.00 0.00 func_a
0.00 0.00 0.00 1 0.00 0.00 func_b
0.00 0.00 0.00 1 0.00 0.00 func_c
If you need print flat profile excluding functions func_a and func_c and full call graph you need call:
$ gprof main gmon.out -b -Pfunc_a -Pfunc_c -q
% cumulative self self total
time seconds seconds calls Ts/call Ts/call name
0.00 0.00 0.00 1 0.00 0.00 func_b
index % time self children called name
0.00 0.00 1/1 main [9]
[1] 0.0 0.00 0.00 1 func_a [1]
-----------------------------------------------
0.00 0.00 1/1 main [9]
[2] 0.0 0.00 0.00 1 func_b [2]
-----------------------------------------------
0.00 0.00 1/1 main [9]
[3] 0.0 0.00 0.00 1 func_c [3]
-----------------------------------------------
If you need print flat profile excluding functions func_a and func_c and call graph excluding func_b you need call:
$ gprof main gmon.out -b -Pfunc_a -Pfunc_c -Qfunc_b
% cumulative self self total
time seconds seconds calls Ts/call Ts/call name
0.00 0.00 0.00 1 0.00 0.00 func_b
index % time self children called name
0.00 0.00 1/1 main [9]
[1] 0.0 0.00 0.00 1 func_a [1]
-----------------------------------------------
0.00 0.00 1/1 main [9]
[3] 0.0 0.00 0.00 1 func_c [3]
-----------------------------------------------

Answer 3

Unless I've misunderstood what you're asking...
gprof a.out --no-time=function_name
works for me.