Laurent Morichetti
5079410c94
There is a small window where a thread can go to sleep in Monitor::wait after releasing the lock but before another thread notifies the monitor and updates the on-deck thread. A simple approach to fix this problem is to wake-up the Monitor::wait every 10 milliseconds and check if it is on-deck. Change-Id: I4b9abda89d1fc653cdae2b4c84cdda01efde1cf2
140 строки
3.6 KiB
C++
140 строки
3.6 KiB
C++
/* Copyright (c) 2008-present Advanced Micro Devices, Inc.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE. */
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#include "thread/semaphore.hpp"
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#include "thread/thread.hpp"
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#if defined(_WIN32) || defined(__CYGWIN__)
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#include <windows.h>
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#else // !_WIN32
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#include <semaphore.h>
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#include <errno.h>
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#endif // !_WIN32
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namespace amd {
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Semaphore::Semaphore() : state_(0) {
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#ifdef _WIN32
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handle_ = static_cast<void*>(CreateSemaphore(NULL, 0, LONG_MAX, NULL));
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assert(handle_ != NULL && "CreateSemaphore failed");
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#else // !_WIN32
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if (sem_init(&sem_, 0, 0) != 0) {
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fatal("sem_init() failed");
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}
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#endif // !_WIN32
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}
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Semaphore::~Semaphore() {
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#ifdef _WIN32
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if (!CloseHandle(static_cast<HANDLE>(handle_))) {
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fatal("CloseHandle() failed");
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}
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#else // !_WIN32
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if (sem_destroy(&sem_) != 0) {
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fatal("sem_destroy() failed");
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}
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#endif // !WIN32
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}
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void Semaphore::post() {
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int state = state_.load(std::memory_order_relaxed);
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for (;;) {
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if (state > 0) {
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int newstate = state_.load(std::memory_order_acquire);
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if (state == newstate) {
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return;
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}
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state = newstate;
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continue;
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}
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if (state_.compare_exchange_weak(state, state + 1, std::memory_order_acq_rel,
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std::memory_order_acquire)) {
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break;
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}
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}
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if (state < 0) {
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// We have threads waiting on this event.
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#ifdef _WIN32
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ReleaseSemaphore(static_cast<HANDLE>(handle_), 1, NULL);
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#else // !_WIN32
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if (0 != sem_post(&sem_)) {
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fatal("sem_post() failed");
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}
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#endif // !_WIN32
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}
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}
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void Semaphore::wait() {
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if (state_-- > 0) {
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return;
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}
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#ifdef _WIN32
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if (WAIT_OBJECT_0 != WaitForSingleObject(static_cast<HANDLE>(handle_), INFINITE)) {
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fatal("WaitForSingleObject failed");
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}
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#else // !_WIN32
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while (0 != sem_wait(&sem_)) {
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if (EINTR != errno) {
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fatal("sem_wait() failed");
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}
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}
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#endif // !_WIN32
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}
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void Semaphore::timedWait(int millis) {
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if (state_-- > 0) {
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return;
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}
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#ifdef _WIN32
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DWORD status = WaitForSingleObject(static_cast<HANDLE>(handle_), millis);
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if (WAIT_OBJECT_0 != status && WAIT_TIMEOUT != status) {
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fatal("WaitForSingleObject failed");
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}
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#else // !_WIN32
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struct timespec ts;
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if (clock_gettime(CLOCK_REALTIME, &ts) == -1) {
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fatal("clock_gettime() failed");
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}
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ts.tv_sec += millis / 1000;
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ts.tv_nsec += ((long)millis % 1000) * 1000000;
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if (ts.tv_nsec >= 1000000000) {
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ts.tv_sec += 1;
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ts.tv_nsec -= 1000000000;
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}
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int status;
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while ((status = sem_timedwait(&sem_, &ts)) != 0) {
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if (ETIMEDOUT == errno) {
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break;
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} else if (EINTR != errno) {
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fatal("sem_wait() failed");
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}
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}
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#endif // !_WIN32
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}
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} // namespace amd
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