87 خطوط
2.2 KiB
C++
87 خطوط
2.2 KiB
C++
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#include <atomic>
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#include <chrono>
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#include <cstdio>
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#include <cstdlib>
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#include <iostream>
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#include <mutex>
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#include <pthread.h>
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#include <random>
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#include <ratio>
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#include <string>
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#include <thread>
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#include <vector>
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long
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fib(long n)
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{
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return (n < 2) ? n : fib(n - 1) + fib(n - 2);
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}
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#if !defined(MAX_THREADS)
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# define MAX_THREADS 4000
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#endif
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auto total_duration = std::chrono::duration<long, std::nano>{};
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int
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main(int argc, char** argv)
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{
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std::string _name = argv[0];
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auto _pos = _name.find_last_of('/');
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if(_pos != std::string::npos) _name = _name.substr(_pos + 1);
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size_t nthread = 2 * MAX_THREADS;
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size_t concurrency = std::thread::hardware_concurrency();
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long nfib = 35;
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if(argc > 1) nfib = atol(argv[1]);
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if(argc > 2) concurrency = atol(argv[2]);
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if(argc > 3) nthread = atol(argv[3]);
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printf("\n[%s] Threads: %zu\n[%s] concurrency: %zu\n[%s] fibonacci(%li)\n",
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_name.c_str(), nthread, _name.c_str(), concurrency, _name.c_str(), nfib);
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auto threads = std::vector<std::thread>{};
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auto _sync = [_name, &threads]() {
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std::this_thread::yield();
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for(auto& itr : threads)
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itr.join();
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threads.clear();
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};
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threads.reserve(concurrency);
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for(size_t i = 0; i < nthread; ++i)
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{
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if(i > MAX_THREADS - 8)
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{
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printf("[%s] launching thread %zu (max: %d)...\n", _name.c_str(), i,
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MAX_THREADS);
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fflush(stdout);
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}
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threads.emplace_back(
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[](auto n) {
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auto t0 = std::chrono::steady_clock::now();
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n = fib(n);
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(void) n;
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auto diff = (std::chrono::steady_clock::now() - t0);
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static auto _mutex = std::mutex{};
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_mutex.lock();
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total_duration += diff;
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_mutex.unlock();
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},
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nfib);
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if(i % concurrency == (concurrency - 1)) _sync();
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}
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_sync();
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printf("[%s] ... completed with an average of %.3f msec per thread\n", _name.c_str(),
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std::chrono::duration_cast<std::chrono::milliseconds>(total_duration).count() *
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(1.0 / nthread));
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return 0;
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}
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