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1 | #ifndef EP_BARRIER_HPP_INCLUDED |
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2 | #define EP_BARRIER_HPP_INCLUDED |
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3 | |
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4 | |
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5 | namespace ep_lib |
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6 | { |
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7 | |
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8 | class ep_barrier |
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9 | { |
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10 | private: |
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11 | int nbThreads; //<The number of threads for this barrier |
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12 | int currentNbThread; //<The current number of threads waiting |
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13 | bool sense; //<Direct barrier feedback protection |
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14 | omp_lock_t mutex; //<To have an atomic int |
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15 | |
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16 | ep_barrier(ep_barrier&){} |
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17 | ep_barrier& operator=(ep_barrier&){return *this;} |
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18 | |
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19 | public: |
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20 | /** Constructor with the number of threads */ |
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21 | explicit ep_barrier(const int inNbThreads) |
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22 | : nbThreads(inNbThreads), currentNbThread(0), sense(false) { |
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23 | omp_init_lock( &mutex ); |
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24 | } |
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25 | |
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26 | /** Destructor, release the omp lock */ |
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27 | ~ep_barrier(){ |
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28 | omp_destroy_lock( &mutex ); |
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29 | } |
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30 | |
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31 | /** Perform a barrier */ |
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32 | void wait(){ |
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33 | const bool mySense = sense; |
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34 | omp_set_lock( &mutex ); |
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35 | const int nbThreadsArrived = (++currentNbThread); |
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36 | omp_unset_lock( &mutex ); |
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37 | |
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38 | if(nbThreadsArrived == nbThreads) { |
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39 | currentNbThread = 0; |
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40 | sense = !sense; |
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41 | #pragma omp flush |
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42 | } |
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43 | else { |
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44 | volatile const bool* const ptSense = &sense; |
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45 | while( (*ptSense) == mySense){ |
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46 | } |
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47 | } |
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48 | } |
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49 | |
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50 | |
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51 | /** Change the number of threads */ |
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52 | void setNbThreads(const int inNbThread){ |
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53 | omp_set_lock( &mutex ); |
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54 | nbThreads = inNbThread; |
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55 | omp_unset_lock( &mutex ); |
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56 | } |
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57 | }; |
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58 | |
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59 | |
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60 | } |
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61 | |
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62 | |
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63 | |
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64 | #endif // EP_BARRIER_HPP_INCLUDED |
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65 | |
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