===== ParForTest =====

<code c++ parfortest.cpp>
/* -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* ***************************************************************************
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as 
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
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 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
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 *  templates or use macros or inline functions from this file, or you compile
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 *  the GNU General Public License.  This exception does not however
 *  invalidate any other reasons why the executable file might be covered by
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 */

/* Very simple performance test for the FF_PARFOR
 *
 */

#include <cstdlib>
#include <omp.h>

#include <ff/parallel_for.hpp>

#if defined(USE_TBB)
#include <tbb/tbb.h>
#include <tbb/tbb_thread.h>
#include <tbb/parallel_for.h>
#include <tbb/blocked_range.h>
#include <tbb/task_scheduler_init.h>
#endif

/*
 * This random generators are implementing 
 * by following POSIX.1-2001 directives.
 */
#define SIM_RAND_MAX         32767
__thread unsigned long next = 0;
inline static long simRandom(void) {
    next = next * 1103515245 + 12345;
    return((unsigned)(next/65536) % 32768);
}
inline static void simSRandom(unsigned long seed) {
    next = seed;
}
/*
 * In Numerical Recipes in C: The Art of Scientific Computing 
 * (William H. Press, Brian P. Flannery, Saul A. Teukolsky, William T. Vetterling;
 *  New York: Cambridge University Press, 1992 (2nd ed., p. 277))
 */
inline static long simRandomRange(long low, long high) {
    return low + (long) ( ((double) high)* (simRandom() / (SIM_RAND_MAX + 1.0)));
}


using namespace ff;


static inline void compute(long id, int nticks) {
    if (next == 0UL) {
        simSRandom(id + 1L);
    }
    long val = simRandomRange(1,nticks);
    for(volatile long k=0;k<val;++k) ;
}

int main(int argc, char *argv[]) {
    if (argc<4) {
        printf("use: %s numtasks nworkers ticks [chunk=(numtasks/nworkers)]\n", argv[0]);
        return -1;
    }
    const long numtasks = atol(argv[1]);
    const int  nworkers = atoi(argv[2]);
    const int  nticks   = atoi(argv[3]);
    int   chunk = std::max((int)(numtasks/nworkers),1);
    if (argc == 5) 
        chunk = atoi(argv[4]);
    
    FF_PARFOR_INIT(pf, nworkers);

    ffTime(START_TIME);
    FF_PARFOR_START(pf, j,0,numtasks,1, chunk, nworkers) {
        compute(_ff_thread_id, nticks);
    } FF_PARFOR_STOP(pf);
    ffTime(STOP_TIME);
    FF_PARFOR_DONE(pf);

    printf("%d Time  = %g (ms)\n", nworkers, ffTime(GET_TIME));
    return 0;
}
</code>