Files
test/memory_benchmark.cpp

109 lines
2.6 KiB
C++

/* Check cf5-opt.vim defs.
VIM: let g:lcppflags="-std=c++11 -O2 -pthread"
VIM: let g:wcppflags="/O2 /EHsc /DWIN32"
VIM: let g:cppflags=g:Iboost
VIM: let g:ldflags=g:Lboost
VIM: let g:ldlibpath=g:Bboost
VIM: let g:argv=""
VIM-: let g:cf5output=0
*/
#include <iostream>
#include <iomanip>
#include <exception>
#include <chrono>
#include <algorithm>
typedef long long duration_type;
static const size_t ce = 1024L*1024L*1024L;
duration_type scan_read( char * p, const size_t c, const size_t s )
{
auto b = std::chrono::high_resolution_clock::now();
int sum = 0;
char * qe = p+c;
for ( int n =0, ne=ce/c; n < ne; ++n )
for ( size_t i = 0; i < s; ++i )
for ( char * q = p+i; q < qe; q+=s )
sum += *q;
volatile int no_optimization = sum;
auto e = std::chrono::high_resolution_clock::now();
return std::chrono::nanoseconds(e-b).count();
}
duration_type scan_write( char * p, const size_t c, const size_t s )
{
int a = rand();
auto b = std::chrono::high_resolution_clock::now();
char * qe = p+c;
for ( int n =0, ne=ce/c; n < ne; ++n )
for ( size_t i = 0; i < s; ++i )
for ( char * q = p+i; q < qe; q+=s )
*q = a;
auto e = std::chrono::high_resolution_clock::now();
return std::chrono::nanoseconds(e-b).count();
}
template <class F>
void test_steps( F f , char * p, const size_t c, char * nm )
{
f( p, c, 1 ); // First run ignore.
std::cout << std::setw(10) << "steps";
std::cout << std::setw(16) << nm;
std::cout << std::setw(16) << nm;
std::cout << std::setw(16) << nm;
std::cout << std::setw(16) << "average";
std::cout << std::setw(16) << "deviation" << std::endl;
for ( size_t s = 1; s < c; s<<=1 )
{
std::cout << std::setw(10) << s << std::flush;
auto d1 = f( p, c, s );
std::cout << std::setw(16) << d1 << std::flush;
auto d2 = f( p, c, s );
std::cout << std::setw(16) << d2 << std::flush;
auto d3 = f( p, c, s );
std::cout << std::setw(16) << d3 << std::flush;
auto a = (d1+d2+d3)/3;
std::cout << std::setw(16) << a;
auto dev = (std::abs(d1-a)+std::abs(d2-a)+std::abs(d3-a))/3;
std::cout << std::setw(16) << dev << std::endl;
}
}
void test_workingset( const size_t c )
{
char * p = (char*)malloc( c );
std::cout << "Working set " << c << std::endl ;
test_steps( scan_read, p, c, "read" );
test_steps( scan_write, p, c, "write" );
}
int main ( void )
{try{
for ( size_t c = 4096; c <= ce; c <<=1 )
test_workingset( c );
return 0;
}
catch ( const std::exception& e )
{
std::cerr << std::endl
<< "std::exception(\"" << e.what() << "\")." << std::endl;
return 2;
}
catch ( ... )
{
std::cerr << std::endl
<< "unknown exception." << std::endl;
return 1;
}}