Profiling C++ application

Profiling allows you to learn where your program spent its time and which functions called which other functions while it was executing.

To profile C++ application I use GNU profiler.

To compile a source file for profiling, specify the -pg option when you run the compiler. 

g++ -pg -o bin/prog src/prog.cc

Once the program is compiled for profiling, you must run it in order to generate the information that gprof needs.

./bin/prog

After you have a profile data file gmon.out, you can run gprof to interpret the information in it.

gprof -b ./bin/prog

You will get such result:

 Flat profile:
 
 Each sample counts as 0.01 seconds.
  no time accumulated
 
   %   cumulative   self              self     total           
  time   seconds   seconds    calls  Ts/call  Ts/call  name    
   0.00      0.00     0.00        1     0.00     0.00  method1()
   0.00      0.00     0.00        1     0.00     0.00  method2()
   0.00      0.00     0.00        1     0.00     0.00  method3()
  
    Call graph
 
 
 granularity: each sample hit covers 4 byte(s) no time propagated
 
 index % time    self  children    called     name
                 0.00    0.00       1/1           main [4]
 [5]      0.0    0.00    0.00       1         method1() [5]
                 0.00    0.00       1/1           method2() [6]
 -----------------------------------------------
                 0.00    0.00       1/1           method1() [5]
 [6]      0.0    0.00    0.00       1         method2() [6]
                 0.00    0.00       1/1           method3() [7]
 -----------------------------------------------
                 0.00    0.00       1/1           method2() [6]
 [7]      0.0    0.00    0.00       1         method3() [7]
 -----------------------------------------------
  
 Index by function name
 
   [5] method1()               [6] method2()               [7] method3()

To read more about the GNU profiler go here.

HTTP: The Definitive Guide

A few days go I finished reading book HTTP: The Definitive Guide.

Web technology has become the foundation for all sorts of critical networked applications and far-reaching methods of data exchange, and beneath it all is a fundamental protocol: HyperText Transfer Protocol, or HTTP.

This book is about how web applications work, how the core Internet protocols and architectural building blocks interact, and how to correctly implement Internet clients and servers.