taskbits_example.cpp

//
//  taskbits_example.cpp
//  CF4Hep
//
//  Created by Benedikt Hegner on 4/7/12.
//  Copyright (c) 2012 CERN. All rights reserved.
//

// include c++
#include <iostream>
// include tbb
#include "tbb/task_scheduler_init.h"
// include fwk
#include "ExampleChains.h"
#include "Helpers.h"
#include "Skep.h"


tbb::spin_mutex my_mutex;

//===========================
//		Scheduler
//===========================
int schedule(unsigned int events, unsigned int n_parallel) {
    
    // time it
    timestamp_t tstart = get_timestamp();
    
    // set up the scheduler
    Skep skep(events, n_parallel, 100);

    tbb::spin_mutex::scoped_lock lock;
    
    // wait for all jobs completing
    lock.acquire(my_mutex);
    printf("\nWaiting for all completing\n");
    lock.release();
    
    // time it
    timestamp_t tstop = get_timestamp();
    timestamp_t totTime = tstop-tstart;
    printf("elapsed time:\t %llu \n", totTime);
    printf("time/event:\t\t %llu\n",totTime/events);
    return totTime;
}

//===========================
//		MAIN
//===========================

int main(int argc, char *argv[]) {
    
    // default threads
    int num_threads = 4;
    // create a pool of toy algorithms
    
    // command-line parser
    if ( argc > 1 ) num_threads = atoi(argv[1]);
    if ( num_threads < 1 ) exit(1);
    
    // enabling a certain number of working threads
    printf("Init %i working threads\n", num_threads);
    tbb::task_scheduler_init init(num_threads); //apparently this value can be changed only once per application run

    
    // declaring a Whiteboard instance with a number of internal slots
    unsigned int events(4000);
    unsigned int n_parallel(20);
    
    bool test = false;
    if ( argc > 3 && atoi(argv[3]) == 1 ) test = true;
    
    if(test) {
        timestamp_t time = 0;
        int times = 0;
        for (int nn=0; nn<5; ++nn) {
            time += schedule(events, n_parallel);
            ++times;
        }
        printf("%i threads -  Time: %f\n\n\n", num_threads, time/(double)times );
	}
    else {
        schedule(events, n_parallel);
    }
}