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///-*-C++-*-//////////////////////////////////////////////////////////////////
//
// Hoard: A Fast, Scalable, and Memory-Efficient Allocator
//        for Shared-Memory Multiprocessors
// Contact author: Emery Berger, http://www.cs.umass.edu/~emery
//
// Copyright (c) 1998-2003, The University of Texas at Austin.
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as
// published by the Free Software Foundation, http://www.fsf.org.
//
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Library General Public License for more details.
//
//////////////////////////////////////////////////////////////////////////////

/**
 * @file  cache-thrash.cpp
 * @brief cache-thrash is a benchmark that exercises a heap's cache-locality.
 *
 * Try the following (on a P-processor machine):
 *
 *  cache-thrash 1 1000 1 1000000
 *  cache-thrash P 1000 1 1000000
 *
 *  cache-thrash-hoard 1 1000 1 1000000
 *  cache-thrash-hoard P 1000 1 1000000
 *
 *  The ideal is a P-fold speedup.
*/


#include <iostream>
#include <stdlib.h>

using namespace std;

#include "cpuinfo.h"
#include "fred.h"
#include "timer.h"

// This class just holds arguments to each thread.
class workerArg {
public:
	workerArg() {}
	workerArg (int objSize, int repetitions, int iterations)
	: _objSize (objSize),
	 _iterations (iterations),
	 _repetitions (repetitions)
	{}

	int _objSize;
	int _iterations;
	int _repetitions;
};


#if defined(_WIN32)
extern "C" void worker (void * arg)
#else
extern "C" void * worker (void * arg)
#endif
{
	// Repeatedly do the following:
	//   malloc a given-sized object,
	//   repeatedly write on it,
	//   then free it.
	workerArg * w = (workerArg *) arg;
	workerArg w1 = *w;
	for (int i = 0; i < w1._iterations; i++) {
	// Allocate the object.
		char * obj = new char[w1._objSize];
		//    printf ("obj = %p\n", obj);
		// Write into it a bunch of times.
		for (int j = 0; j < w1._repetitions; j++) {
			for (int k = 0; k < w1._objSize; k++) {
				obj[k] = (char) k;
				volatile char ch = obj[k];
				ch++;
			}
		}
		// Free the object.
		delete [] obj;
	}
#if !defined(_WIN32)
	return NULL;
#endif
}


int main (int argc, char * argv[])
{
	int nthreads;
	int iterations;
	int objSize;
	int repetitions;
	
	if (argc > 4) {
		nthreads = atoi(argv[1]);
		iterations = atoi(argv[2]);
		objSize = atoi(argv[3]);
		repetitions = atoi(argv[4]);
	} else {
	cerr << "Usage: " << argv[0] << " nthreads iterations objSize repetitions" << endl;
	exit(1);
	}

	HL::Fred * threads = new HL::Fred[nthreads];
	HL::Fred::setConcurrency (HL::CPUInfo::getNumProcessors());
    
	int i;
  
	HL::Timer t;
	t.start();
  
	workerArg * w = new workerArg[nthreads];
    
	for (i = 0; i < nthreads; i++) {
		w[i] = workerArg (objSize, repetitions / nthreads, iterations);
		threads[i].create (&worker, (void *) &w[i]);
	}
	for (i = 0; i < nthreads; i++) {
		threads[i].join();
	}
	t.stop();

	delete [] threads;
	delete [] w;

	cout << "Time elapsed = " << (double) t << " seconds." << endl;
}