[SYCL][NFC] Rename misleading queue_impl::MSupportOOO variable (#8342)

The variable is supposed to indicate that we failed to create an OOO
native queue and we need to emulate it if its value is false. Rename to
MEmulateOOO to avoid confusion with in-order/out-of-order SYCL queues.

Author: sergey-semenov

sycl/source/detail/queue_impl.cpp

@@ -117,7 +117,7 @@ event queue_impl::memset(const std::shared_ptr<detail::queue_impl> &Self,
     }
   }
   // Track only if we won't be able to handle it with piQueueFinish.
-  if (!MSupportOOO)
+  if (MEmulateOOO)
     addSharedEvent(ResEvent);
   return MDiscardEvents ? createDiscardedEvent() : ResEvent;
 }
@@ -180,7 +180,7 @@ event queue_impl::memcpy(const std::shared_ptr<detail::queue_impl> &Self,
     }
   }
   // Track only if we won't be able to handle it with piQueueFinish.
-  if (!MSupportOOO)
+  if (MEmulateOOO)
     addSharedEvent(ResEvent);
   return MDiscardEvents ? createDiscardedEvent() : ResEvent;
 }
@@ -224,7 +224,7 @@ event queue_impl::mem_advise(const std::shared_ptr<detail::queue_impl> &Self,
     }
   }
   // Track only if we won't be able to handle it with piQueueFinish.
-  if (!MSupportOOO)
+  if (MEmulateOOO)
     addSharedEvent(ResEvent);
   return MDiscardEvents ? createDiscardedEvent() : ResEvent;
 }
@@ -237,12 +237,12 @@ void queue_impl::addEvent(const event &Event) {
     // if there is no command on the event, we cannot track it with MEventsWeak
     // as that will leave it with no owner. Track in MEventsShared only if we're
     // unable to call piQueueFinish during wait.
-    if (is_host() || !MSupportOOO)
+    if (is_host() || MEmulateOOO)
       addSharedEvent(Event);
   }
   // As long as the queue supports piQueueFinish we only need to store events
   // for unenqueued commands and host tasks.
-  else if (is_host() || !MSupportOOO || EImpl->getHandleRef() == nullptr) {
+  else if (is_host() || MEmulateOOO || EImpl->getHandleRef() == nullptr) {
     std::weak_ptr<event_impl> EventWeakPtr{EImpl};
     std::lock_guard<std::mutex> Lock{MMutex};
     MEventsWeak.push_back(std::move(EventWeakPtr));
@@ -253,7 +253,7 @@ void queue_impl::addEvent(const event &Event) {
 /// but some events have no other owner. In this case,
 /// addSharedEvent will have the queue track the events via a shared pointer.
 void queue_impl::addSharedEvent(const event &Event) {
-  assert(is_host() || !MSupportOOO);
+  assert(is_host() || MEmulateOOO);
   std::lock_guard<std::mutex> Lock(MMutex);
   // Events stored in MEventsShared are not released anywhere else aside from
   // calls to queue::wait/wait_and_throw, which a user application might not
@@ -388,7 +388,7 @@ void queue_impl::wait(const detail::code_location &CodeLoc) {
   // directly. Otherwise, only wait for unenqueued or host task events, starting
   // from the latest submitted task in order to minimize total amount of calls,
   // then handle the rest with piQueueFinish.
-  const bool SupportsPiFinish = !is_host() && MSupportOOO;
+  const bool SupportsPiFinish = !is_host() && !MEmulateOOO;
   for (auto EventImplWeakPtrIt = WeakEvents.rbegin();
        EventImplWeakPtrIt != WeakEvents.rend(); ++EventImplWeakPtrIt) {
     if (std::shared_ptr<event_impl> EventImplSharedPtr =

sycl/source/detail/queue_impl.hpp

@@ -449,8 +449,8 @@ class queue_impl {
     // If creating out-of-order queue failed and this property is not
     // supported (for example, on FPGA), it will return
     // PI_ERROR_INVALID_QUEUE_PROPERTIES and will try to create in-order queue.
-    if (MSupportOOO && Error == PI_ERROR_INVALID_QUEUE_PROPERTIES) {
-      MSupportOOO = false;
+    if (!MEmulateOOO && Error == PI_ERROR_INVALID_QUEUE_PROPERTIES) {
+      MEmulateOOO = true;
       Queue = createQueue(QueueOrder::Ordered);
     } else {
       Plugin.checkPiResult(Error);
@@ -493,7 +493,7 @@ class queue_impl {
   /// \return a raw PI queue handle. The returned handle is not retained. It
   /// is caller responsibility to make sure queue is still alive.
   RT::PiQueue &getHandleRef() {
-    if (MSupportOOO)
+    if (!MEmulateOOO)
       return MQueues[0];
 
     return getExclusiveQueueHandleRef();
@@ -713,8 +713,9 @@ class queue_impl {
   size_t MNextQueueIdx = 0;
 
   const bool MHostQueue = false;
-  // Assume OOO support by default.
-  bool MSupportOOO = true;
+  /// Indicates that a native out-of-order queue could not be created and we
+  /// need to emulate it with multiple native in-order queues.
+  bool MEmulateOOO = false;
 
   // Buffer to store assert failure descriptor
   buffer<AssertHappened, 1> MAssertHappenedBuffer;