[clang-tools-extra] r349032 - [clangd] Avoid emitting Queued status when we are able to acquire the Barrier.

[Haojian Wu via cfe-commits]

Author: hokein
Date: Thu Dec 13 05:09:50 2018
New Revision: 349032

URL: http://llvm.org/viewvc/llvm-project?rev=349032&view=rev
Log:
[clangd] Avoid emitting Queued status when we are able to acquire the Barrier.

Reviewers: ilya-biryukov

Subscribers: javed.absar, ioeric, MaskRay, jkorous, arphaman, kadircet, cfe-commits

Differential Revision: https://reviews.llvm.org/D55359

Modified:
    clang-tools-extra/trunk/clangd/TUScheduler.cpp
    clang-tools-extra/trunk/clangd/Threading.cpp
    clang-tools-extra/trunk/clangd/Threading.h
    clang-tools-extra/trunk/unittests/clangd/TUSchedulerTests.cpp

Modified: clang-tools-extra/trunk/clangd/TUScheduler.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clangd/TUScheduler.cpp?rev=349032&r1=349031&r2=349032&view=diff
==============================================================================
--- clang-tools-extra/trunk/clangd/TUScheduler.cpp (original)
+++ clang-tools-extra/trunk/clangd/TUScheduler.cpp Thu Dec 13 05:09:50 2018
@@ -634,9 +634,11 @@ void ASTWorker::run() {
     } // unlock Mutex
 
     {
-      // FIXME: only emit this status when the Barrier couldn't be acquired.
-      emitTUStatus({TUAction::Queued, Req.Name});
-      std::lock_guard<Semaphore> BarrierLock(Barrier);
+      std::unique_lock<Semaphore> Lock(Barrier, std::try_to_lock);
+      if (!Lock.owns_lock()) {
+        emitTUStatus({TUAction::Queued, Req.Name});
+        Lock.lock();
+      }
       WithContext Guard(std::move(Req.Ctx));
       trace::Span Tracer(Req.Name);
       emitTUStatus({TUAction::RunningAction, Req.Name});

Modified: clang-tools-extra/trunk/clangd/Threading.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clangd/Threading.cpp?rev=349032&r1=349031&r2=349032&view=diff
==============================================================================
--- clang-tools-extra/trunk/clangd/Threading.cpp (original)
+++ clang-tools-extra/trunk/clangd/Threading.cpp Thu Dec 13 05:09:50 2018
@@ -28,6 +28,15 @@ void Notification::wait() const {
 
 Semaphore::Semaphore(std::size_t MaxLocks) : FreeSlots(MaxLocks) {}
 
+bool Semaphore::try_lock() {
+  std::unique_lock<std::mutex> Lock(Mutex);
+  if (FreeSlots > 0) {
+    --FreeSlots;
+    return true;
+  }
+  return false;
+}
+
 void Semaphore::lock() {
   trace::Span Span("WaitForFreeSemaphoreSlot");
   // trace::Span can also acquire locks in ctor and dtor, we make sure it

Modified: clang-tools-extra/trunk/clangd/Threading.h
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clangd/Threading.h?rev=349032&r1=349031&r2=349032&view=diff
==============================================================================
--- clang-tools-extra/trunk/clangd/Threading.h (original)
+++ clang-tools-extra/trunk/clangd/Threading.h Thu Dec 13 05:09:50 2018
@@ -42,6 +42,7 @@ class Semaphore {
 public:
   Semaphore(std::size_t MaxLocks);
 
+  bool try_lock();
   void lock();
   void unlock();
 

Modified: clang-tools-extra/trunk/unittests/clangd/TUSchedulerTests.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/unittests/clangd/TUSchedulerTests.cpp?rev=349032&r1=349031&r2=349032&view=diff
==============================================================================
--- clang-tools-extra/trunk/unittests/clangd/TUSchedulerTests.cpp (original)
+++ clang-tools-extra/trunk/unittests/clangd/TUSchedulerTests.cpp Thu Dec 13 05:09:50 2018
@@ -698,13 +698,11 @@ TEST_F(TUSchedulerTests, TUStatus) {
   EXPECT_THAT(CaptureTUStatus.AllStatus,
               ElementsAre(
                   // Statuses of "Update" action.
-                  TUState(TUAction::Queued, "Update"),
                   TUState(TUAction::RunningAction, "Update"),
                   TUState(TUAction::BuildingPreamble, "Update"),
                   TUState(TUAction::BuildingFile, "Update"),
 
                   // Statuses of "Definitions" action
-                  TUState(TUAction::Queued, "Definitions"),
                   TUState(TUAction::RunningAction, "Definitions"),
                   TUState(TUAction::Idle, /*No action*/ "")));
 }