Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* This Source Code Form is subject to the terms of the Mozilla Public
       3             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       4             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       5             : 
       6             : #include "ThreadResponsiveness.h"
       7             : #include "platform.h"
       8             : #include "nsComponentManagerUtils.h"
       9             : #include "nsThreadUtils.h"
      10             : #include "nsITimer.h"
      11             : #include "mozilla/Mutex.h"
      12             : 
      13             : using mozilla::Mutex;
      14             : using mozilla::MutexAutoLock;
      15             : using mozilla::TimeStamp;
      16             : 
      17             : class CheckResponsivenessTask : public mozilla::Runnable,
      18             :                                 public nsITimerCallback {
      19             : public:
      20           0 :   CheckResponsivenessTask()
      21           0 :     : mozilla::Runnable("CheckResponsivenessTask")
      22             :     , mLastTracerTime(TimeStamp::Now())
      23             :     , mMutex("CheckResponsivenessTask")
      24             :     , mTimer(nullptr)
      25             :     , mHasEverBeenSuccessfullyDispatched(false)
      26           0 :     , mStop(false)
      27             :   {
      28           0 :   }
      29             : 
      30             : protected:
      31           0 :   ~CheckResponsivenessTask()
      32           0 :   {
      33           0 :   }
      34             : 
      35             : public:
      36             : 
      37             :   // Must be called from the same thread every time. Call that the "update"
      38             :   // thread, because it's the thread that ThreadResponsiveness::Update() is
      39             :   // called on. In reality it's the profiler's sampler thread.
      40           0 :   void DoFirstDispatchIfNeeded()
      41             :   {
      42           0 :     if (mHasEverBeenSuccessfullyDispatched) {
      43           0 :       return;
      44             :     }
      45             : 
      46             :     // Dispatching can fail during early startup, particularly when
      47             :     // MOZ_PROFILER_STARTUP is used.
      48           0 :     nsresult rv = NS_DispatchToMainThread(this);
      49           0 :     if (NS_SUCCEEDED(rv)) {
      50           0 :       mHasEverBeenSuccessfullyDispatched = true;
      51             :     }
      52             :   }
      53             : 
      54             :   // Can only run on the main thread.
      55           0 :   NS_IMETHOD Run() override
      56             :   {
      57           0 :     MutexAutoLock mon(mMutex);
      58           0 :     if (mStop)
      59           0 :       return NS_OK;
      60             : 
      61             :     // This is raced on because we might pause the thread here
      62             :     // for profiling so if we tried to use a monitor to protect
      63             :     // mLastTracerTime we could deadlock. We're risking seeing
      64             :     // a partial write which will show up as an outlier in our
      65             :     // performance data.
      66           0 :     mLastTracerTime = TimeStamp::Now();
      67           0 :     if (!mTimer) {
      68           0 :       mTimer = do_CreateInstance("@mozilla.org/timer;1");
      69             :     }
      70           0 :     mTimer->InitWithCallback(this, 16, nsITimer::TYPE_ONE_SHOT);
      71             : 
      72           0 :     return NS_OK;
      73             :   }
      74             : 
      75           0 :   NS_IMETHOD Notify(nsITimer* aTimer) final
      76             :   {
      77           0 :     NS_DispatchToMainThread(this);
      78           0 :     return NS_OK;
      79             :   }
      80             : 
      81           0 :   void Terminate() {
      82           0 :     MutexAutoLock mon(mMutex);
      83           0 :     mStop = true;
      84           0 :   }
      85             : 
      86           0 :   const TimeStamp& GetLastTracerTime() const {
      87           0 :     return mLastTracerTime;
      88             :   }
      89             : 
      90             :   NS_DECL_ISUPPORTS_INHERITED
      91             : 
      92             : private:
      93             :   TimeStamp mLastTracerTime;
      94             :   Mutex mMutex;
      95             :   nsCOMPtr<nsITimer> mTimer;
      96             :   bool mHasEverBeenSuccessfullyDispatched; // only accessed on the "update" thread
      97             :   bool mStop;
      98             : };
      99             : 
     100           0 : NS_IMPL_ISUPPORTS_INHERITED(CheckResponsivenessTask, mozilla::Runnable,
     101             :                             nsITimerCallback)
     102             : 
     103           0 : ThreadResponsiveness::ThreadResponsiveness()
     104           0 :   : mActiveTracerEvent(new CheckResponsivenessTask())
     105             : {
     106           0 :   MOZ_COUNT_CTOR(ThreadResponsiveness);
     107           0 : }
     108             : 
     109           0 : ThreadResponsiveness::~ThreadResponsiveness()
     110             : {
     111           0 :   MOZ_COUNT_DTOR(ThreadResponsiveness);
     112           0 :   mActiveTracerEvent->Terminate();
     113           0 : }
     114             : 
     115             : void
     116           0 : ThreadResponsiveness::Update()
     117             : {
     118           0 :   mActiveTracerEvent->DoFirstDispatchIfNeeded();
     119           0 :   mLastTracerTime = mActiveTracerEvent->GetLastTracerTime();
     120           0 : }
     121             :