1 /* boost nondet_random_speed.cpp performance test
2 *
3 * Copyright Jens Maurer 2000
4 * Distributed under the Boost Software License, Version 1.0. (See
5 * accompanying file LICENSE_1_0.txt or copy at
6 * http://www.boost.org/LICENSE_1_0.txt)
7 *
8 * $Id$
9 *
10 */
11
12 #include <iostream>
13 #include <string>
14 #include <boost/timer.hpp>
15 #include <boost/random/random_device.hpp>
16
17 // set to your CPU frequency
18 static const double cpu_frequency = 1.87 * 1e9;
19
show_elapsed(double end,int iter,const std::string & name)20 static void show_elapsed(double end, int iter, const std::string & name)
21 {
22 double usec = end/iter*1e6;
23 double cycles = usec * cpu_frequency/1e6;
24 std::cout << name << ": "
25 << usec*1e3 << " nsec/loop = "
26 << cycles << " CPU cycles"
27 << std::endl;
28 }
29
30 template<class Result, class RNG>
timing(RNG & rng,int iter,const std::string & name)31 static void timing(RNG & rng, int iter, const std::string& name)
32 {
33 volatile Result tmp; // make sure we're not optimizing too much
34 boost::timer t;
35 for(int i = 0; i < iter; i++)
36 tmp = rng();
37 show_elapsed(t.elapsed(), iter, name);
38 }
39
40 template<class RNG>
run(int iter,const std::string & name)41 void run(int iter, const std::string & name)
42 {
43 RNG rng;
44 timing<long>(rng, iter, name);
45 }
46
main(int argc,char * argv[])47 int main(int argc, char*argv[])
48 {
49 if(argc != 2) {
50 std::cerr << "usage: " << argv[0] << " iterations" << std::endl;
51 return 1;
52 }
53
54 int iter = std::atoi(argv[1]);
55
56 boost::random::random_device dev;
57 timing<unsigned int>(dev, iter, "random_device");
58
59 return 0;
60 }
61