libs/ui/tests/BufferHubEventFd_test.cpp - android_frameworks_native - Gitiles

 /*
  * Copyright 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "BufferHubEventFdTest"

 #include <sys/epoll.h>
 #include <sys/eventfd.h>

 #include <array>
 #include <condition_variable>
 #include <mutex>
 #include <thread>

 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <log/log.h>
 #include <ui/BufferHubEventFd.h>

 namespace android {

 namespace {

 const int kTimeout = 100;
 const std::chrono::milliseconds kTimeoutMs(kTimeout);

 using ::testing::Contains;
 using BufferHubEventFdTest = ::testing::Test;

 } // namespace

 TEST_F(BufferHubEventFdTest, EventFd_testSingleEpollFd) {
     BufferHubEventFd eventFd;
     ASSERT_TRUE(eventFd.isValid());

     base::unique_fd epollFd(epoll_create(64));
     epoll_event e = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 0}};

     ASSERT_GE(epollFd.get(), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

     std::array<epoll_event, 1> events;
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

     eventFd.signal();
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);

     // The epoll fd is edge triggered, so it only responds to the eventFd once.
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);
 }

 TEST_F(BufferHubEventFdTest, EventFd_testClear) {
     BufferHubEventFd eventFd;
     ASSERT_TRUE(eventFd.isValid());

     base::unique_fd epollFd(epoll_create(64));
     epoll_event e = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 0}};

     ASSERT_GE(epollFd.get(), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

     eventFd.signal();
     eventFd.clear();

     std::array<epoll_event, 1> events;
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);
 }

 TEST_F(BufferHubEventFdTest, EventFd_testDupEventFd) {
     BufferHubEventFd eventFd;
     ASSERT_TRUE(eventFd.isValid());

     base::unique_fd epollFd(epoll_create(64));
     epoll_event e = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 0}};

     ASSERT_GE(epollFd.get(), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

     // Technically, the dupliated eventFd and the original eventFd are pointing
     // to the same kernel object. This test signals the duplicated eventFd but epolls the origianl
     // eventFd.
     base::unique_fd dupedEventFd(dup(eventFd.get()));
     ASSERT_GE(dupedEventFd.get(), 0);

     std::array<epoll_event, 1> events;
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

     eventfd_write(dupedEventFd.get(), 1);
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);

     // The epoll fd is edge triggered, so it only responds to the eventFd once.
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

     eventfd_write(dupedEventFd.get(), 1);

     eventfd_t value;
     eventfd_read(dupedEventFd.get(), &value);
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);
 }

 TEST_F(BufferHubEventFdTest, EventFd_testTwoEpollFds) {
     BufferHubEventFd eventFd;
     ASSERT_TRUE(eventFd.isValid());

     base::unique_fd epollFd1(epoll_create(64));
     base::unique_fd epollFd2(epoll_create(64));
     epoll_event e = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 0}};

     ASSERT_GE(epollFd1.get(), 0);
     ASSERT_GE(epollFd2.get(), 0);

     // Register the same eventFd to two EpollFds.
     ASSERT_EQ(epoll_ctl(epollFd1.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);
     ASSERT_EQ(epoll_ctl(epollFd2.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

     std::array<epoll_event, 1> events;
     EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 0);
     EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 0);

     eventFd.signal();
     EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 1);
     EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 1);

     // The epoll fd is edge triggered, so it only responds to the eventFd once.
     EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 0);
     EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 0);

     eventFd.signal();
     EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 1);

     eventFd.clear();
     EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 0);
     EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 0);
 }

 TEST_F(BufferHubEventFdTest, EventFd_testTwoEventFds) {
     BufferHubEventFd eventFd1;
     BufferHubEventFd eventFd2;

     ASSERT_TRUE(eventFd1.isValid());
     ASSERT_TRUE(eventFd2.isValid());

     base::unique_fd epollFd(epoll_create(64));
     epoll_event e1 = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 1}};
     epoll_event e2 = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 2}};

     ASSERT_GE(epollFd.get(), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd1.get(), &e1), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd2.get(), &e2), 0);

     std::array<epoll_event, 2> events;
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

     // Signal one by one.
     eventFd1.signal();
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);
     EXPECT_EQ(events[0].data.u32, e1.data.u32);

     eventFd2.signal();
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);
     EXPECT_EQ(events[0].data.u32, e2.data.u32);

     // Signal both.
     eventFd1.signal();
     eventFd2.signal();
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 2);

     uint32_t u32s[] = {events[0].data.u32, events[1].data.u32};
     EXPECT_THAT(u32s, Contains(e1.data.u32));
     EXPECT_THAT(u32s, Contains(e2.data.u32));

     // The epoll fd is edge triggered, so it only responds to the eventFd once.
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

     eventFd1.signal();
     eventFd2.signal();
     eventFd2.clear();
     EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);
 }

 TEST_F(BufferHubEventFdTest, EventFd_testPollingThreadWithTwoEventFds) {
     BufferHubEventFd eventFd1;
     BufferHubEventFd eventFd2;

     ASSERT_TRUE(eventFd1.isValid());
     ASSERT_TRUE(eventFd2.isValid());

     base::unique_fd epollFd(epoll_create(64));
     epoll_event e1 = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 1}};
     epoll_event e2 = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 2}};

     ASSERT_GE(epollFd.get(), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd1.get(), &e1), 0);
     ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd2.get(), &e2), 0);

     int countEvent1 = 0;
     int countEvent2 = 0;
     std::atomic<bool> stop{false};
     std::mutex mx;
     std::condition_variable cv;

     std::thread pollingThread([&] {
         std::array<epoll_event, 2> events;
         while (true) {
             if (stop.load()) {
                 break;
             }
             int ret = epoll_wait(epollFd.get(), events.data(), events.size(), kTimeout);
             ALOGE_IF(ret < 0 && errno != ETIMEDOUT, "Epoll failed.");

             std::lock_guard<std::mutex> lock(mx);
             for (int i = 0; i < ret; i++) {
                 if (events[i].data.u32 == e1.data.u32) {
                     countEvent1++;
                     cv.notify_one();
                 } else if (events[i].data.u32 == e2.data.u32) {
                     countEvent2++;
                     cv.notify_one();
                 }
             }
         }
     });

     {
         std::unique_lock<std::mutex> lock(mx);

         eventFd1.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent1 == 1; }));

         eventFd1.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent1 == 2; }));

         eventFd2.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent2 == 1; }));

         eventFd1.clear();
         eventFd2.clear();
         EXPECT_EQ(countEvent1, 2);
         EXPECT_EQ(countEvent2, 1);

         eventFd1.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent1 == 3; }));

         eventFd2.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent2 == 2; }));
     }

     stop.store(true);
     pollingThread.join();
 }

 TEST_F(BufferHubEventFdTest, EventFd_testTwoPollingThreads) {
     BufferHubEventFd eventFd;
     ASSERT_TRUE(eventFd.isValid());

     base::unique_fd epollFd1(epoll_create(64));
     base::unique_fd epollFd2(epoll_create(64));
     epoll_event e = {.events = EPOLLIN | EPOLLET, .data = {.u32 = 0}};

     ASSERT_GE(epollFd1.get(), 0);
     ASSERT_GE(epollFd2.get(), 0);

     // Register the same eventFd to two EpollFds.
     ASSERT_EQ(epoll_ctl(epollFd1.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);
     ASSERT_EQ(epoll_ctl(epollFd2.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

     int countEpoll1 = 0;
     int countEpoll2 = 0;
     std::atomic<bool> stop{false};
     std::mutex mx;
     std::condition_variable cv;

     std::thread pollingThread1([&] {
         std::array<epoll_event, 1> events;
         while (!stop.load()) {
             int ret = epoll_wait(epollFd1.get(), events.data(), events.size(), kTimeout);
             ALOGE_IF(ret < 0 && errno != ETIMEDOUT, "Epoll failed.");

             if (ret > 0) {
                 std::lock_guard<std::mutex> lock(mx);
                 countEpoll1++;
                 cv.notify_one();
             }
         }
     });

     std::thread pollingThread2([&] {
         std::array<epoll_event, 1> events;
         while (!stop.load()) {
             int ret = epoll_wait(epollFd2.get(), events.data(), events.size(), kTimeout);
             ALOGE_IF(ret < 0 && errno != ETIMEDOUT, "Epoll failed.");

             if (ret > 0) {
                 std::lock_guard<std::mutex> lock(mx);
                 countEpoll2++;
                 cv.notify_one();
             }
         }
     });

     {
         std::unique_lock<std::mutex> lock(mx);

         eventFd.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll1 == 1; }));
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll2 == 1; }));

         eventFd.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll1 == 2; }));
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll2 == 2; }));

         eventFd.clear();
         EXPECT_EQ(countEpoll1, 2);
         EXPECT_EQ(countEpoll2, 2);

         eventFd.signal();
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll1 == 3; }));
         EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll2 == 3; }));
     }

     stop.store(true);
     pollingThread1.join();
     pollingThread2.join();
 }

 } // namespace android
	/*
	* Copyright 2018 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "BufferHubEventFdTest"

	#include <sys/epoll.h>
	#include <sys/eventfd.h>

	#include <array>
	#include <condition_variable>
	#include <mutex>
	#include <thread>

	#include <gmock/gmock.h>
	#include <gtest/gtest.h>
	#include <log/log.h>
	#include <ui/BufferHubEventFd.h>

	namespace android {

	namespace {

	const int kTimeout = 100;
	const std::chrono::milliseconds kTimeoutMs(kTimeout);

	using ::testing::Contains;
	using BufferHubEventFdTest = ::testing::Test;

	} // namespace

	TEST_F(BufferHubEventFdTest, EventFd_testSingleEpollFd) {
	BufferHubEventFd eventFd;
	ASSERT_TRUE(eventFd.isValid());

	base::unique_fd epollFd(epoll_create(64));
	epoll_event e = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 0}};

	ASSERT_GE(epollFd.get(), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

	std::array<epoll_event, 1> events;
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

	eventFd.signal();
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);

	// The epoll fd is edge triggered, so it only responds to the eventFd once.
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);
	}

	TEST_F(BufferHubEventFdTest, EventFd_testClear) {
	BufferHubEventFd eventFd;
	ASSERT_TRUE(eventFd.isValid());

	base::unique_fd epollFd(epoll_create(64));
	epoll_event e = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 0}};

	ASSERT_GE(epollFd.get(), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

	eventFd.signal();
	eventFd.clear();

	std::array<epoll_event, 1> events;
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);
	}

	TEST_F(BufferHubEventFdTest, EventFd_testDupEventFd) {
	BufferHubEventFd eventFd;
	ASSERT_TRUE(eventFd.isValid());

	base::unique_fd epollFd(epoll_create(64));
	epoll_event e = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 0}};

	ASSERT_GE(epollFd.get(), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

	// Technically, the dupliated eventFd and the original eventFd are pointing
	// to the same kernel object. This test signals the duplicated eventFd but epolls the origianl
	// eventFd.
	base::unique_fd dupedEventFd(dup(eventFd.get()));
	ASSERT_GE(dupedEventFd.get(), 0);

	std::array<epoll_event, 1> events;
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

	eventfd_write(dupedEventFd.get(), 1);
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);

	// The epoll fd is edge triggered, so it only responds to the eventFd once.
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

	eventfd_write(dupedEventFd.get(), 1);

	eventfd_t value;
	eventfd_read(dupedEventFd.get(), &value);
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);
	}

	TEST_F(BufferHubEventFdTest, EventFd_testTwoEpollFds) {
	BufferHubEventFd eventFd;
	ASSERT_TRUE(eventFd.isValid());

	base::unique_fd epollFd1(epoll_create(64));
	base::unique_fd epollFd2(epoll_create(64));
	epoll_event e = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 0}};

	ASSERT_GE(epollFd1.get(), 0);
	ASSERT_GE(epollFd2.get(), 0);

	// Register the same eventFd to two EpollFds.
	ASSERT_EQ(epoll_ctl(epollFd1.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);
	ASSERT_EQ(epoll_ctl(epollFd2.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

	std::array<epoll_event, 1> events;
	EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 0);
	EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 0);

	eventFd.signal();
	EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 1);
	EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 1);

	// The epoll fd is edge triggered, so it only responds to the eventFd once.
	EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 0);
	EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 0);

	eventFd.signal();
	EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 1);

	eventFd.clear();
	EXPECT_EQ(epoll_wait(epollFd1.get(), events.data(), events.size(), 0), 0);
	EXPECT_EQ(epoll_wait(epollFd2.get(), events.data(), events.size(), 0), 0);
	}

	TEST_F(BufferHubEventFdTest, EventFd_testTwoEventFds) {
	BufferHubEventFd eventFd1;
	BufferHubEventFd eventFd2;

	ASSERT_TRUE(eventFd1.isValid());
	ASSERT_TRUE(eventFd2.isValid());

	base::unique_fd epollFd(epoll_create(64));
	epoll_event e1 = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 1}};
	epoll_event e2 = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 2}};

	ASSERT_GE(epollFd.get(), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd1.get(), &e1), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd2.get(), &e2), 0);

	std::array<epoll_event, 2> events;
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

	// Signal one by one.
	eventFd1.signal();
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);
	EXPECT_EQ(events[0].data.u32, e1.data.u32);

	eventFd2.signal();
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);
	EXPECT_EQ(events[0].data.u32, e2.data.u32);

	// Signal both.
	eventFd1.signal();
	eventFd2.signal();
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 2);

	uint32_t u32s[] = {events[0].data.u32, events[1].data.u32};
	EXPECT_THAT(u32s, Contains(e1.data.u32));
	EXPECT_THAT(u32s, Contains(e2.data.u32));

	// The epoll fd is edge triggered, so it only responds to the eventFd once.
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 0);

	eventFd1.signal();
	eventFd2.signal();
	eventFd2.clear();
	EXPECT_EQ(epoll_wait(epollFd.get(), events.data(), events.size(), 0), 1);
	}

	TEST_F(BufferHubEventFdTest, EventFd_testPollingThreadWithTwoEventFds) {
	BufferHubEventFd eventFd1;
	BufferHubEventFd eventFd2;

	ASSERT_TRUE(eventFd1.isValid());
	ASSERT_TRUE(eventFd2.isValid());

	base::unique_fd epollFd(epoll_create(64));
	epoll_event e1 = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 1}};
	epoll_event e2 = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 2}};

	ASSERT_GE(epollFd.get(), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd1.get(), &e1), 0);
	ASSERT_EQ(epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd2.get(), &e2), 0);

	int countEvent1 = 0;
	int countEvent2 = 0;
	std::atomic<bool> stop{false};
	std::mutex mx;
	std::condition_variable cv;

	std::thread pollingThread([&] {
	std::array<epoll_event, 2> events;
	while (true) {
	if (stop.load()) {
	break;
	}
	int ret = epoll_wait(epollFd.get(), events.data(), events.size(), kTimeout);
	ALOGE_IF(ret < 0 && errno != ETIMEDOUT, "Epoll failed.");

	std::lock_guard<std::mutex> lock(mx);
	for (int i = 0; i < ret; i++) {
	if (events[i].data.u32 == e1.data.u32) {
	countEvent1++;
	cv.notify_one();
	} else if (events[i].data.u32 == e2.data.u32) {
	countEvent2++;
	cv.notify_one();
	}
	}
	}
	});

	{
	std::unique_lock<std::mutex> lock(mx);

	eventFd1.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent1 == 1; }));

	eventFd1.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent1 == 2; }));

	eventFd2.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent2 == 1; }));

	eventFd1.clear();
	eventFd2.clear();
	EXPECT_EQ(countEvent1, 2);
	EXPECT_EQ(countEvent2, 1);

	eventFd1.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent1 == 3; }));

	eventFd2.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEvent2 == 2; }));
	}

	stop.store(true);
	pollingThread.join();
	}

	TEST_F(BufferHubEventFdTest, EventFd_testTwoPollingThreads) {
	BufferHubEventFd eventFd;
	ASSERT_TRUE(eventFd.isValid());

	base::unique_fd epollFd1(epoll_create(64));
	base::unique_fd epollFd2(epoll_create(64));
	epoll_event e = {.events = EPOLLIN \| EPOLLET, .data = {.u32 = 0}};

	ASSERT_GE(epollFd1.get(), 0);
	ASSERT_GE(epollFd2.get(), 0);

	// Register the same eventFd to two EpollFds.
	ASSERT_EQ(epoll_ctl(epollFd1.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);
	ASSERT_EQ(epoll_ctl(epollFd2.get(), EPOLL_CTL_ADD, eventFd.get(), &e), 0);

	int countEpoll1 = 0;
	int countEpoll2 = 0;
	std::atomic<bool> stop{false};
	std::mutex mx;
	std::condition_variable cv;

	std::thread pollingThread1([&] {
	std::array<epoll_event, 1> events;
	while (!stop.load()) {
	int ret = epoll_wait(epollFd1.get(), events.data(), events.size(), kTimeout);
	ALOGE_IF(ret < 0 && errno != ETIMEDOUT, "Epoll failed.");

	if (ret > 0) {
	std::lock_guard<std::mutex> lock(mx);
	countEpoll1++;
	cv.notify_one();
	}
	}
	});

	std::thread pollingThread2([&] {
	std::array<epoll_event, 1> events;
	while (!stop.load()) {
	int ret = epoll_wait(epollFd2.get(), events.data(), events.size(), kTimeout);
	ALOGE_IF(ret < 0 && errno != ETIMEDOUT, "Epoll failed.");

	if (ret > 0) {
	std::lock_guard<std::mutex> lock(mx);
	countEpoll2++;
	cv.notify_one();
	}
	}
	});

	{
	std::unique_lock<std::mutex> lock(mx);

	eventFd.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll1 == 1; }));
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll2 == 1; }));

	eventFd.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll1 == 2; }));
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll2 == 2; }));

	eventFd.clear();
	EXPECT_EQ(countEpoll1, 2);
	EXPECT_EQ(countEpoll2, 2);

	eventFd.signal();
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll1 == 3; }));
	EXPECT_TRUE(cv.wait_for(lock, kTimeoutMs, [&] { return countEpoll2 == 3; }));
	}

	stop.store(true);
	pollingThread1.join();
	pollingThread2.join();
	}

	} // namespace android