[SYCL]Fixes a performance issue due to https://github.com/intel/llvm/…

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -4111,8 +4111,13 @@ pi_result piEventGetInfo(pi_event Event, pi_event_info ParamName,
       // Lock automatically releases when this goes out of scope.
       std::lock_guard<std::mutex> lock(Event->Queue->PiQueueMutex);
 
-      if (auto Res = Event->Queue->executeOpenCommandList())
-        return Res;
+      // Only do the execute of the open command list if the event that
+      // is being queried and event that is to be signalled by something
+      // currently in that open command list.
+      if (Event->Queue->ZeOpenCommandList == Event->ZeCommandList) {
+        if (auto Res = Event->Queue->executeOpenCommandList())
+          return Res;
+      }
     }
 
     ze_result_t ZeResult;

sycl/source/detail/queue_impl.cpp

@@ -122,14 +122,21 @@ void queue_impl::addSharedEvent(const event &Event) {
   // of them can be released.
   const size_t EventThreshold = 128;
   if (MEventsShared.size() >= EventThreshold) {
+    // Generally, the vector is ordered so that the oldest events are in the
+    // front and the newer events are in the end.  So, search to find the first
+    // event that isn't yet complete.  All the events prior to that can be
+    // erased. This could leave some few events further on that have completed
+    // not yet erased, but that is OK.  This cleanup doesn't have to be perfect.
+    // This also keeps the algorithm linear rather than quadratic because it
+    // doesn't continually recheck things towards the back of the list that
+    // really haven't had time to complete.
     MEventsShared.erase(
-        std::remove_if(
-            MEventsShared.begin(), MEventsShared.end(),
-            [](const event &E) {
-              return E.get_info<info::event::command_execution_status>() ==
+        MEventsShared.begin(),
+        std::find_if(
+            MEventsShared.begin(), MEventsShared.end(), [](const event &E) {
+              return E.get_info<info::event::command_execution_status>() !=
                      info::event_command_status::complete;
-            }),
-        MEventsShared.end());
+            }));
   }
   MEventsShared.push_back(Event);
 }