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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#define EIGEN_USE_THREADS
#include <iostream>
#include <unordered_set>
#include "main.h"
#include <Eigen/CXX11/ThreadPool>
struct Counter {
Counter() = default;
void inc() {
// Check that mutation happens only in a thread that created this counter.
VERIFY_IS_EQUAL(std::this_thread::get_id(), created_by);
counter_value++;
}
int value() { return counter_value; }
std::thread::id created_by;
int counter_value = 0;
};
struct InitCounter {
void operator()(Counter& counter) {
counter.created_by = std::this_thread::get_id();
}
};
void test_simple_thread_local() {
int num_threads = internal::random<int>(4, 32);
Eigen::ThreadPool thread_pool(num_threads);
Eigen::ThreadLocal<Counter, InitCounter> counter(num_threads, InitCounter());
int num_tasks = 3 * num_threads;
Eigen::Barrier barrier(num_tasks);
for (int i = 0; i < num_tasks; ++i) {
thread_pool.Schedule([&counter, &barrier]() {
Counter& local = counter.local();
local.inc();
std::this_thread::sleep_for(std::chrono::milliseconds(100));
barrier.Notify();
});
}
barrier.Wait();
counter.ForEach(
[](std::thread::id, Counter& cnt) { VERIFY_IS_EQUAL(cnt.value(), 3); });
}
void test_zero_sized_thread_local() {
Eigen::ThreadLocal<Counter, InitCounter> counter(0, InitCounter());
Counter& local = counter.local();
local.inc();
int total = 0;
counter.ForEach([&total](std::thread::id, Counter& cnt) {
total += cnt.value();
VERIFY_IS_EQUAL(cnt.value(), 1);
});
VERIFY_IS_EQUAL(total, 1);
}
// All thread local values fits into the lock-free storage.
void test_large_number_of_tasks_no_spill() {
int num_threads = internal::random<int>(4, 32);
Eigen::ThreadPool thread_pool(num_threads);
Eigen::ThreadLocal<Counter, InitCounter> counter(num_threads, InitCounter());
int num_tasks = 10000;
Eigen::Barrier barrier(num_tasks);
for (int i = 0; i < num_tasks; ++i) {
thread_pool.Schedule([&counter, &barrier]() {
Counter& local = counter.local();
local.inc();
barrier.Notify();
});
}
barrier.Wait();
int total = 0;
std::unordered_set<std::thread::id> unique_threads;
counter.ForEach([&](std::thread::id id, Counter& cnt) {
total += cnt.value();
unique_threads.insert(id);
});
VERIFY_IS_EQUAL(total, num_tasks);
// Not all threads in a pool might be woken up to execute submitted tasks.
// Also thread_pool.Schedule() might use current thread if queue is full.
VERIFY_IS_EQUAL(
unique_threads.size() <= (static_cast<size_t>(num_threads + 1)), true);
}
// Lock free thread local storage is too small to fit all the unique threads,
// and it spills to a map guarded by a mutex.
void test_large_number_of_tasks_with_spill() {
int num_threads = internal::random<int>(4, 32);
Eigen::ThreadPool thread_pool(num_threads);
Eigen::ThreadLocal<Counter, InitCounter> counter(1, InitCounter());
int num_tasks = 10000;
Eigen::Barrier barrier(num_tasks);
for (int i = 0; i < num_tasks; ++i) {
thread_pool.Schedule([&counter, &barrier]() {
Counter& local = counter.local();
local.inc();
barrier.Notify();
});
}
barrier.Wait();
int total = 0;
std::unordered_set<std::thread::id> unique_threads;
counter.ForEach([&](std::thread::id id, Counter& cnt) {
total += cnt.value();
unique_threads.insert(id);
});
VERIFY_IS_EQUAL(total, num_tasks);
// Not all threads in a pool might be woken up to execute submitted tasks.
// Also thread_pool.Schedule() might use current thread if queue is full.
VERIFY_IS_EQUAL(
unique_threads.size() <= (static_cast<size_t>(num_threads + 1)), true);
}
EIGEN_DECLARE_TEST(cxx11_tensor_thread_local) {
CALL_SUBTEST(test_simple_thread_local());
CALL_SUBTEST(test_zero_sized_thread_local());
CALL_SUBTEST(test_large_number_of_tasks_no_spill());
CALL_SUBTEST(test_large_number_of_tasks_with_spill());
}
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