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/*  Example of master-worker computation:  
 *               
 *                       --------------------- <--
 *                      |                     |   |
 *                      |        ---> Worker--    |
 *                      v       |                 |
 *                 Scheduler --- ---> Worker------ 
 *                      ^       |
 *                      |        ---> Worker--
 *                      |                     |
 *                       ---------------------
 *
 *
 */
 
 
 
#include <cstdlib>
#include <cstdio>
#include <string>
#include <ff/farm.hpp>
#include <ff/mapping_utils.hpp>
 
using namespace ff;
 
class Scheduler: public ff_node {
public:
    Scheduler(unsigned streamlen, ff_loadbalancer *lb=0):
        lb(lb), numtasks(streamlen), seed(111) {}
 
    int svc_init() {
        printf("Scheduler is on core %d\n", ff_getMyCpu());
        srandom(seed);
        return 0;
    }
 
    void * svc(void *task) {
        if (task==NULL) { // first time
            for(size_t i=0;i<numtasks;++i)
                ff_send_out(new long(random() % 10));
            return GO_ON;
        }
        const long t = *(static_cast<long*>(task));
        //printf("Scheduler: got %ld from %d\n", t, lb->get_channel_id());
        if ( t > 0 ) ff_send_out(task);
        else --numtasks;
 
        return (numtasks>0)?GO_ON:NULL;
    }
private:    
    ff_loadbalancer *lb;
    unsigned numtasks;
    unsigned seed;
};
 
class Worker: public ff_node {
public:
    int svc_init() {
        printf("Worker(%d) is on core %d\n", get_my_id(),ff_getMyCpu());
        return 0;
    }
 
    void *svc(void *task) {
        long *t = static_cast<long*>(task);
        printf("Worker(%d): got %ld\n", get_my_id(), *t);
        --*t;        
        return task;
    }
};
 
int main(int argc, char * argv[]) {
    if (argc!=3) {
        std::cerr << "use: "  << argv[0] << " streamlen nworkers\n";
        return -1;
    }
    long streamlen = atol(argv[1]);
    long nworkers  = atoi(argv[2]);
 
    ff_farm<> farm;
    farm.add_emitter(new Scheduler(streamlen)); //, farm.getlb()));
 
    std::vector<ff_node*> w;
    for(int i=0;i<nworkers;++i)
        w.push_back(new Worker);
    farm.add_workers(w);
    farm.wrap_around();
 
    // - try to comment this code to see where threads are pinned by default
    // - try to comment this code and to compile with -DNO_DEFAULT_MAPPING
#if 1
    // pinning threads to specific cores
    const int ncores = ff_numCores(); // gets the number of cores
    std::string s;
    for(int i=0;i<ncores;++i) {
        s = s+std::to_string(i)+",";
    }
    s=std::to_string(nworkers % ncores)+","+s.substr(0,s.find_last_of(","));
    printf("The mapping string is: %s\n", s.c_str());
    threadMapper::instance()->setMappingList(s.c_str());
#endif
 
    if (farm.run_and_wait_end()<0) {
        error("running farm\n");
        return -1;
    }
    std::cerr << "DONE, pipe  time= " << farm.ffTime() << " (ms)\n";
    return 0;
}