Using GPROF

This command will generate a test file:

gcc -lm -pg sobel.c
./a.out
gprof a.out > test
  

test file:

%      cumulative  self             self     total           
   
 100.27    0.04     0.04        1    40.11    40.11  sobel_filtering
 0.00      0.04     0.00        1     0.00     0.00  load_image_data
 0.00      0.04     0.00        1     0.00     0.00  save_image_data