JMemoryUsage.cc

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#include <string>
#include <iostream>
#include <iomanip>
#include <vector>

#include "JSystem/JShell.hh"
#include "JSystem/JSystemToolkit.hh"

#include "Jeep/JPrint.hh"
#include "Jeep/JParser.hh"
#include "Jeep/JMessage.hh"


/**
 * \file
 *
 * Example program to show memory usage.
 * \author mdejong
 */
int main(int argc, char **argv)
{
  using namespace std;
  using namespace JPP;

  size_t size_B;
  int    debug;

  try {

    JParser<> zap("Example program to show memory usage.");

    zap['M'] = make_field(size_B)  =  1<<25;
    zap['d'] = make_field(debug)   =  3;

    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }

  typedef long long int  data_type;

  const size_t size = size_B / sizeof(data_type);

  {
    cout << endl;
    cout << "Memory usage (start)  " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    data_type* buffer = new data_type[size];

    cout << "Memory usage (new)    " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    for (size_t i = 0; i != size; ++i) {
      buffer[i] = i;
    }

    cout << "Memory usage (assign) " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    delete[] buffer;

    cout << "Memory usage (delete) " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
  }
  {
    cout << endl;
    cout << "Memory usage (start)  " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    vector<data_type> buffer(size);

    cout << "Memory usage (vector) " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    buffer.clear();
    
    cout << "Memory usage (clear)  " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    {
      vector<data_type> zbuf;

      buffer.swap(zbuf);
    }

    cout << "Memory usage (swap)   " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
  }
  {
    cout << endl;
    cout << "Memory usage (start)  " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    size_t N = 10;

    vector< vector<data_type> > buffer(N);

    for (size_t i = 0; i != N; ++i) {
      buffer[i].resize(size / N);
    }

    cout << "Memory usage (vector) " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    buffer.clear();
    
    cout << "Memory usage (clear)  " << FIXED(5,2) << getMemoryUsage() << "%" << endl;

    {
      vector< vector<data_type> > zbuf;

      buffer.swap(zbuf);
    }

    cout << "Memory usage (swap)   " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
  }
}