agent
40a3535393
ParallelFor runs a counted loop across a fixed set of threads created up front and hands out indices from an atomic counter, so the calling thread shares the work. A thread-start hook runs once per helper thread.
66 lines
1.7 KiB
C++
66 lines
1.7 KiB
C++
#include "ParallelFor.hpp"
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#include "UnitTest++/UnitTest++.h"
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#include <atomic>
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#include <chrono>
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#include <mutex>
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#include <set>
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#include <thread>
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#include <vector>
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using namespace tp;
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SUITE(ParallelFor) {
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TEST(EveryIndexRunsOnce) {
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ParallelFor parallel(4);
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std::vector<std::atomic<int>> hits(1000);
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parallel.run(hits.size(), [&hits](size_t index) { hits[index]++; });
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for (const auto& hit : hits)
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CHECK_EQUAL(1, hit.load());
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}
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TEST(RunsAreRepeatableAndReturnWhenDone) {
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ParallelFor parallel(3);
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for (int round = 0; round < 200; round++) {
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std::atomic<int> sum{ 0 };
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parallel.run(37, [&sum](size_t index) { sum += (int) index; });
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CHECK_EQUAL(666, sum.load());
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}
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}
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TEST(WorkIsSharedWithHelperThreads) {
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ParallelFor parallel(4);
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CHECK_EQUAL(4u, parallel.threads());
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std::mutex mutex;
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std::set<std::thread::id> threads;
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parallel.run(64, [&](size_t) {
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std::this_thread::sleep_for(std::chrono::microseconds(500));
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std::lock_guard lock(mutex);
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threads.insert(std::this_thread::get_id());
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});
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CHECK(threads.size() > 1);
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}
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TEST(SingleThreadRunsInline) {
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ParallelFor parallel(1);
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const std::thread::id caller = std::this_thread::get_id();
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bool inline_ = true;
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parallel.run(10, [&](size_t) { inline_ = inline_ && std::this_thread::get_id() == caller; });
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CHECK(inline_);
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parallel.run(0, [](size_t) {});
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}
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TEST(OnStartRunsForEachHelperThread) {
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std::mutex mutex;
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std::set<size_t> indices;
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ParallelFor parallel(4, [&](size_t index) {
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std::lock_guard lock(mutex);
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indices.insert(index);
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});
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parallel.run(8, [](size_t) {});
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CHECK_EQUAL(3u, indices.size());
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for (size_t index = 1; index < 4; index++)
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CHECK(indices.count(index) != 0);
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}
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}
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