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#include <xenium/chase_work_stealing_deque.hpp>
#include <gtest/gtest.h>
#include <vector>
#include <thread>
#include <random>
namespace {
struct node {
int v;
};
struct ChaseWorkStealingDeque: testing::Test {};
TEST(ChaseWorkStealingDeque, push_try_pop_returns_pushed_element)
{
auto n = std::make_unique<node>();
xenium::chase_work_stealing_deque<node> queue;
EXPECT_TRUE(queue.try_push(n.get()));
node* elem;
EXPECT_TRUE(queue.try_pop(elem));
EXPECT_EQ(n.get(), elem);
}
TEST(ChaseWorkStealingDeque, push_try_steal_returns_pushed_element)
{
auto n = std::make_unique<node>();
xenium::chase_work_stealing_deque<node> queue;
EXPECT_TRUE(queue.try_push(n.get()));
node* elem;
EXPECT_TRUE(queue.try_steal(elem));
EXPECT_EQ(n.get(), elem);
}
TEST(ChaseWorkStealingDeque, push_two_items_steal_returns_them_in_FIFO_order)
{
auto n1 = std::make_unique<node>();
auto n2 = std::make_unique<node>();
xenium::chase_work_stealing_deque<node> queue;
EXPECT_TRUE(queue.try_push(n1.get()));
EXPECT_TRUE(queue.try_push(n2.get()));
node* elem;
EXPECT_TRUE(queue.try_steal(elem));
EXPECT_EQ(n1.get(), elem);
EXPECT_TRUE(queue.try_steal(elem));
EXPECT_EQ(n2.get(), elem);
}
TEST(ChaseWorkStealingDeque, push_two_items_pop_returns_them_in_LIFO_order)
{
auto n1 = std::make_unique<node>();
auto n2 = std::make_unique<node>();
xenium::chase_work_stealing_deque<node> queue;
EXPECT_TRUE(queue.try_push(n1.get()));
EXPECT_TRUE(queue.try_push(n2.get()));
node* elem;
EXPECT_TRUE(queue.try_pop(elem));
EXPECT_EQ(n2.get(), elem);
EXPECT_TRUE(queue.try_pop(elem));
EXPECT_EQ(n1.get(), elem);
}
TEST(ChaseWorkStealingDeque, push_pop_steal_many)
{
constexpr unsigned count = 4000;
auto n = std::make_unique<node>();
xenium::chase_work_stealing_deque<node> queue;
for (int x = 0; x < 3; ++x) {
for (unsigned i = 0; i < count; ++i)
ASSERT_TRUE(queue.try_push(n.get()));
node *v;
for (unsigned i = 0; i < count; ++i) {
if (i % 2 == 0)
ASSERT_TRUE(queue.try_pop(v));
else
ASSERT_TRUE(queue.try_steal(v));
}
}
}
TEST(ChaseWorkStealingDeque, parallel_usage)
{
constexpr unsigned num_threads = 8;
constexpr unsigned num_nodes = num_threads * 8;
#ifdef DEBUG
constexpr int MaxIterations = 100000;
#else
constexpr int MaxIterations = 1000000;
#endif
xenium::chase_work_stealing_deque<node> queues[num_threads];
std::unique_ptr<node> nodes[num_nodes];
std::thread threads[num_threads];
for (unsigned i = 0; i < num_nodes; ++i) {
nodes[i] = std::make_unique<node>();
nodes[i]->v = 1;
queues[i % num_threads].try_push(nodes[i].get());
}
std::atomic<bool> start{false};
for (unsigned i = 0; i < num_threads; ++i)
{
threads[i] = std::thread([thread_idx = i, &start, &queues, num_threads, MaxIterations]()
{
// oh my... MSVC complains if these variables are NOT captured; clang complains if they ARE captured.
(void)num_threads;
(void)MaxIterations;
std::mt19937 rand;
rand.seed(thread_idx);
node* n = nullptr;
while (!start.load()) ; // wait for start signal
for (int j = 0; j < MaxIterations; ++j) {
if (n != nullptr) {
++n->v;
EXPECT_EQ(1, n->v);
EXPECT_TRUE(queues[thread_idx].try_push(n));
n = nullptr;
} else {
auto idx = rand() % num_threads;
if (idx == thread_idx && queues[thread_idx].size() > 0) {
if (queues[idx].try_pop(n)) {
EXPECT_NE(nullptr, n);
--n->v;
EXPECT_EQ(0, n->v);
}
} else {
if (queues[idx].try_steal(n)) {
EXPECT_NE(nullptr, n);
--n->v;
EXPECT_EQ(0, n->v);
}
}
}
}
if (n != nullptr) {
++n->v;
queues[thread_idx].try_push(n);
}
});
}
start.store(true);
for (auto& thread : threads)
thread.join();
}
}
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