P4 to Git Change 1082950 by lmoriche@lmoriche_opencl_dev on 2014/09/30 16:50:37

ECR #304775 - Implement the changes recommended in review#5943

	Pre-checkin: http://ocltc.amd.com:8111/viewModification.html?modId=40717&personal=true&buildTypeId=&tab=vcsModificationBuilds&show_all_builds=true

Affected files ...

... //depot/stg/opencl/drivers/opencl/runtime/platform/command.cpp#65 edit
... //depot/stg/opencl/drivers/opencl/runtime/platform/memory.cpp#109 edit
... //depot/stg/opencl/drivers/opencl/runtime/thread/semaphore.cpp#7 edit
... //depot/stg/opencl/drivers/opencl/runtime/utils/concurrent.hpp#6 edit


[ROCm/clr commit: aaf533287b]

projects/clr/rocclr/runtime/platform/command.cpp

@@ -129,10 +129,8 @@ Event::setCallback(cl_int status, Event::CallBackFunction callback, void* data)
     }
 
     entry->next_ = callbacks_;
-    while (!callbacks_.compare_exchange_weak(entry->next_, entry)) {
-        // Someone else is also updating the head of the linked list! reload.
-        entry->next_ = callbacks_;
-    }
+    while (!callbacks_.compare_exchange_weak(entry->next_, entry))
+        ; // Someone else is also updating the head of the linked list! reload.
 
     // Check if the event has already reached 'status'
     if (status_ <= status && entry->callback_ != CallBackFunction(0)) {

projects/clr/rocclr/runtime/platform/memory.cpp

@@ -439,10 +439,8 @@ Memory::setDestructorCallback(DestructorCallBackFunction callback, void* data)
     }
 
     entry->next_ = destructorCallbacks_;
-    while (!destructorCallbacks_.compare_exchange_weak(entry->next_, entry)) {
-        // Someone else is also updating the head of the linked list! reload.
-        entry->next_ = destructorCallbacks_;
-    }
+    while (!destructorCallbacks_.compare_exchange_weak(entry->next_, entry))
+        ; // Someone else is also updating the head of the linked list! reload.
 
     return true;
 }

projects/clr/rocclr/runtime/thread/semaphore.cpp

@@ -43,9 +43,8 @@ Semaphore::~Semaphore()
 void
 Semaphore::post()
 {
-    int state;
-    while (true) {
-        state = state_;
+    int state = state_;
+    for (;;) {
         if (state > 0) {
             if (state == state_.load(std::memory_order_acquire)) {
                 return;

projects/clr/rocclr/runtime/utils/concurrent.hpp

@@ -151,11 +151,11 @@ ConcurrentLinkedQueue<T,N>::enqueue(T elem)
     node->value_ = elem;
     node->next_ = NULL;
 
-    while (true) {
+    for (;;) {
         typename Node::Ptr tail = tail_.load(std::memory_order_acquire);
         typename Node::Ptr next =
             tail->ptr()->next_.load(std::memory_order_acquire);
-        if (tail == tail_.load(std::memory_order_acquire)) {
+        if (likely(tail == tail_.load(std::memory_order_acquire))) {
             if (next->ptr() == NULL) {
                 if (tail->ptr()->next_.compare_exchange_weak(
                         next, Node::ptr(node, next->tag()+1),
@@ -179,12 +179,12 @@ template <typename T, int N>
 inline T
 ConcurrentLinkedQueue<T,N>::dequeue()
 {
-    while (true) {
+    for (;;) {
         typename Node::Ptr head = head_.load(std::memory_order_acquire);
         typename Node::Ptr tail = tail_.load(std::memory_order_acquire);
         typename Node::Ptr next =
             head->ptr()->next_.load(std::memory_order_acquire);
-        if (head == head_.load(std::memory_order_acquire)) {
+        if (likely(head == head_.load(std::memory_order_acquire))) {
             if (head->ptr() == tail->ptr()) {
                 if (next->ptr() == NULL) {
                     return NULL;