Avoid lock for last queued command

Use atomics for last queued command update Change-Id: I759e9d78ea72f23c0d45dbede6250b231e122276
2020-05-29 11:06:55 -04:00
parent a811cfc567
commit dc4e09a63a
2 changed files with 13 additions and 13 deletions
@@ -192,25 +192,27 @@ bool HostQueue::isEmpty() {

 void HostQueue::setLastQueuedCommand(Command* lastCommand) {
  // Set last submitted command
-  ScopedLock l(lastCmdLock_);
-  if (lastEnqueueCommand_ != nullptr) {
-    lastEnqueueCommand_->release();
+  Command* lastEnqueueCommand =
+    lastEnqueueCommand_.exchange(lastCommand, std::memory_order_acq_rel);
+  if (lastEnqueueCommand != nullptr) {
+    lastEnqueueCommand->release();
  }
-  lastEnqueueCommand_ = lastCommand;
  if (lastCommand != nullptr) {
-    lastEnqueueCommand_->retain();
+    lastCommand->retain();
  }
 }

 Command* HostQueue::getLastQueuedCommand(bool retain) {
  // Get last submitted command
-  ScopedLock l(lastCmdLock_);
-
-  if (retain && lastEnqueueCommand_ != nullptr) {
-    lastEnqueueCommand_->retain();
+  Command* lastEnqueueCommand = lastEnqueueCommand_.load(std::memory_order_acquire);
+  if (lastEnqueueCommand == nullptr) {
+    return nullptr;
  }

-  return lastEnqueueCommand_;
+  if (retain) {
+    lastEnqueueCommand->retain();
+  }
+  return lastEnqueueCommand;
 }

 DeviceQueue::~DeviceQueue() {