This article is just a quick reference for profiing C/C++ source code using gprof. C/C++ source code can be profiled using gprof in three steps.

  1. Compile the sources and link the program with profiling options “-pg” 
    bash# gcc  -pg -g -c source1.c source2.c
bash# gcc  -pg -o myapp source1.o source2.o
  2. Execute the program to generate profiling output in gmon.out 
    bash# ./myapp
  3. Analyze the profiling output with gprof. It prints the list of functions which have taken more time during the execution of process. This list is in descending order so probably you would want to start optimizing the code in the same order.The output also shows how many times a function is invoked during the execution.
    4. bash# gmon ./myapp gmon.out
Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls  ms/call  ms/call  name
 33.34      0.02     0.02     7208     0.00     0.00  open
 16.67      0.03     0.01      244     0.04     0.12  offtime
 16.67      0.04     0.01        8     1.25     1.25  memccpy
 16.67      0.05     0.01        7     1.43     1.43  write
 16.67      0.06     0.01                             mcount
  0.00      0.06     0.00      236     0.00     0.00  tzset
  0.00      0.06     0.00      192     0.00     0.00  tolower