Question

i’m analysing my code with gprof, and i get the following output:

   %   cumulative   self              self     total           
  time  seconds   seconds    calls  ms/call  ms/call  name    
 59.22      0.58     0.58       48    12.09    18.81  _GLOBAL__sub_I_inputHeight

inputHeight is a global variable. I have no idea what GLOBAL_sub_I_inputHeight means, but it is called 48 times, and consumes 60% (0,6) of the exection time.

Any ideas?

Answer 1

when you run run a gprofiled program, it writes the data in a file, usually gmon.out. That file contains the addresses of the functions, not the names. When you read the data with the gprof utility, it resolves the names using the debugging information present in the program.

That means that if you run the program, recompile it and execute gprof without re-running the program, the output is meaningless.