JMemoryUsage.cc

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#include <string>
#include <iostream>
#include <iomanip>
#include <vector>
#include <unistd.h>
 
#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;
  unsigned int sleep_us;
  bool         use;
  int          debug;
 
  try {
 
    JParser<> zap("Example program to show memory usage.");
 
    zap['M'] = make_field(size_B)   =  1<<25;
    zap['s'] = make_field(sleep_us) =  1;
    zap['u'] = make_field(use);
    zap['d'] = make_field(debug)    =  3;
 
    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }
 
  if (sleep_us == 0) {
    sleep_us = 1;
  }
 
  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];
 
    usleep(sleep_us);
 
    cout << "Memory usage (new)       " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
 
    if (use) {
 
      for (size_t i = 0; i != size; ++i) {
        buffer[i] = i;
      }
 
      usleep(sleep_us);
 
      cout << "Memory usage (assign)    " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
    }
 
    delete[] buffer;
 
    usleep(sleep_us);
 
    cout << "Memory usage (delete)    " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
  }
  {
    cout << endl;
    cout << "Memory usage (start)     " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
 
    vector<data_type> buffer;
 
    buffer.reserve(size);
 
    cout << "Memory usage (vector)    " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
 
    if (use) {
 
      for (size_t i = 0; i != size; ++i) {
        buffer.push_back(i);
      }
 
      usleep(sleep_us);
 
      cout << "Memory usage (push_back) " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
    }
 
    buffer.clear();
    
    usleep(sleep_us);
 
    cout << "Memory usage (clear)     " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
 
    {
      vector<data_type> zbuf;
 
      buffer.swap(zbuf);
    }
 
    usleep(sleep_us);
 
    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);
 
    if (use) {
 
      for (size_t i = 0; i != N; ++i) {
        buffer[i].resize(size / N);
      }
 
      usleep(sleep_us);
 
      cout << "Memory usage (vector)    " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
    }
    
    buffer.clear();
    
    usleep(sleep_us);
 
    cout << "Memory usage (clear)     " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
 
    {
      vector< vector<data_type> > zbuf;
 
      buffer.swap(zbuf);
    }
 
    usleep(sleep_us);
 
    cout << "Memory usage (swap)      " << FIXED(5,2) << getMemoryUsage() << "%" << endl;
  }
}