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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2016 Dmitry Vyukov <dvyukov@google.com>
// Copyright (C) 2016 Benoit Steiner <benoit.steiner.goog@gmail.com>
//
// 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 "main.h"
#include "Eigen/CXX11/ThreadPool"
#include "Eigen/CXX11/Tensor"
static void test_create_destroy_empty_pool()
{
// Just create and destroy the pool. This will wind up and tear down worker
// threads. Ensure there are no issues in that logic.
for (int i = 0; i < 16; ++i) {
ThreadPool tp(i);
}
}
static void test_parallelism(bool allow_spinning)
{
// Test we never-ever fail to match available tasks with idle threads.
const int kThreads = 16; // code below expects that this is a multiple of 4
ThreadPool tp(kThreads, allow_spinning);
VERIFY_IS_EQUAL(tp.NumThreads(), kThreads);
VERIFY_IS_EQUAL(tp.CurrentThreadId(), -1);
for (int iter = 0; iter < 100; ++iter) {
std::atomic<int> running(0);
std::atomic<int> done(0);
std::atomic<int> phase(0);
// Schedule kThreads tasks and ensure that they all are running.
for (int i = 0; i < kThreads; ++i) {
tp.Schedule([&]() {
const int thread_id = tp.CurrentThreadId();
VERIFY_GE(thread_id, 0);
VERIFY_LE(thread_id, kThreads - 1);
running++;
while (phase < 1) {
}
done++;
});
}
while (running != kThreads) {
}
running = 0;
phase = 1;
// Now, while the previous tasks exit, schedule another kThreads tasks and
// ensure that they are running.
for (int i = 0; i < kThreads; ++i) {
tp.Schedule([&, i]() {
running++;
while (phase < 2) {
}
// When all tasks are running, half of tasks exit, quarter of tasks
// continue running and quarter of tasks schedule another 2 tasks each.
// Concurrently main thread schedules another quarter of tasks.
// This gives us another kThreads tasks and we ensure that they all
// are running.
if (i < kThreads / 2) {
} else if (i < 3 * kThreads / 4) {
running++;
while (phase < 3) {
}
done++;
} else {
for (int j = 0; j < 2; ++j) {
tp.Schedule([&]() {
running++;
while (phase < 3) {
}
done++;
});
}
}
done++;
});
}
while (running != kThreads) {
}
running = 0;
phase = 2;
for (int i = 0; i < kThreads / 4; ++i) {
tp.Schedule([&]() {
running++;
while (phase < 3) {
}
done++;
});
}
while (running != kThreads) {
}
phase = 3;
while (done != 3 * kThreads) {
}
}
}
static void test_cancel()
{
ThreadPool tp(2);
// Schedule a large number of closure that each sleeps for one second. This
// will keep the thread pool busy for much longer than the default test timeout.
for (int i = 0; i < 1000; ++i) {
tp.Schedule([]() {
std::this_thread::sleep_for(std::chrono::milliseconds(2000));
});
}
// Cancel the processing of all the closures that are still pending.
tp.Cancel();
}
static void test_pool_partitions() {
const int kThreads = 2;
ThreadPool tp(kThreads);
// Assign each thread to its own partition, so that stealing other work only
// occurs globally when a thread is idle.
std::vector<std::pair<unsigned, unsigned>> steal_partitions(kThreads);
for (int i = 0; i < kThreads; ++i) {
steal_partitions[i] = std::make_pair(i, i + 1);
}
tp.SetStealPartitions(steal_partitions);
std::atomic<int> running(0);
std::atomic<int> done(0);
std::atomic<int> phase(0);
// Schedule kThreads tasks and ensure that they all are running.
for (int i = 0; i < kThreads; ++i) {
tp.Schedule([&]() {
const int thread_id = tp.CurrentThreadId();
VERIFY_GE(thread_id, 0);
VERIFY_LE(thread_id, kThreads - 1);
++running;
while (phase < 1) {
}
++done;
});
}
while (running != kThreads) {
}
// Schedule each closure to only run on thread 'i' and verify that it does.
for (int i = 0; i < kThreads; ++i) {
tp.ScheduleWithHint(
[&, i]() {
++running;
const int thread_id = tp.CurrentThreadId();
VERIFY_IS_EQUAL(thread_id, i);
while (phase < 2) {
}
++done;
},
i, i + 1);
}
running = 0;
phase = 1;
while (running != kThreads) {
}
running = 0;
phase = 2;
}
EIGEN_DECLARE_TEST(cxx11_non_blocking_thread_pool)
{
CALL_SUBTEST(test_create_destroy_empty_pool());
CALL_SUBTEST(test_parallelism(true));
CALL_SUBTEST(test_parallelism(false));
CALL_SUBTEST(test_cancel());
CALL_SUBTEST(test_pool_partitions());
}
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