usermode/library/malloc-hoard-old/benchmarks/cache-scratch/cache-scratch.cpp

//
// Hoard: A Fast, Scalable, and Memory-Efficient Allocator
//        for Shared-Memory Multiprocessors
// Contact author: Emery Berger, http://www.cs.utexas.edu/users/emery
//
// Copyright (c) 1998-2000, 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.
//

/*
  cache-scratch.cpp
  ------------------------------------------------------------------------
  cache-scratch is a benchmark that exercises a heap's cache-locality.
  An allocator that allows multiple threads to re-use the same small
  object (possibly all in one cache-line) will scale poorly, while
  an allocator like Hoard will exhibit near-linear scaling.
  ------------------------------------------------------------------------
  @(#) $Id: cache-scratch.cpp,v 1.12 2000/09/28 17:01:30 emery Exp $
  ------------------------------------------------------------------------
  Emery Berger                    | <http://www.cs.utexas.edu/users/emery>
  Department of Computer Sciences |             <http://www.cs.utexas.edu>
  University of Texas at Austin   |                <http://www.utexas.edu>
  ========================================================================
*/

/* Try the following (on a P-processor machine):

   cache-scratch 1 1000 1 1000000
   cache-scratch P 1000 1 1000000

   cache-scratch-hoard 1 1000 1 1000000
   cache-scratch-hoard P 1000 1 1000000

   The ideal is a P-fold speedup.
*/


#include "arch-specific.h"
#include "timer.h"

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

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

  char * _object;
  int _objSize;
  int _iterations;
  int _repetitions;
};


extern "C" void * worker (void * arg)
{
  // free the object we were given.
  // Then, repeatedly do the following:
  //   malloc a given-sized object,
  //   repeatedly write on it,
  //   then free it.
  workerArg * w = (workerArg *) arg;
  delete w->_object;
  for (int i = 0; i < w->_iterations; i++) {
    // Allocate the object.
    char * obj = new char[w->_objSize];
    // Write into it a bunch of times.
    for (int j = 0; j < w->_repetitions; j++) {
      for (int k = 0; k < w->_objSize; k++) {
        obj[k] = (char) k;
        volatile char ch = obj[k];
        ch++;
      }
    }
    // Free the object.
    delete [] obj;
  }
  delete w;
  return NULL;
}


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);
  }

  hoardThreadType * threads = new hoardThreadType[nthreads];
  hoardSetConcurrency (hoardGetNumProcessors());

  int i;

  // Allocate nthreads objects and distribute them among the threads.
  char ** objs = new char * [nthreads];
  for (i = 0; i < nthreads; i++) {
    objs[i] = new char[objSize];
  }

  Timer t;
  t.start();

  for (i = 0; i < nthreads; i++) {
    workerArg * w = new workerArg (objs[i], objSize, repetitions / nthreads, iterations);
    hoardCreateThread (threads[i], worker, (void *) w);
  }
  for (i = 0; i < nthreads; i++) {
    hoardJoinThread (threads[i]);
  }
  t.stop();

  delete [] threads;
  delete [] objs;

  cout << "Time elapsed = " << (double) t << " seconds." << endl;
  return 0;
}

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