Optimize report delivery timing for subscribe

--Between min and max, only send the report when the handler is dirty
--At max, mNeedRefreshSubscribe is set, server would send the report

src/app/ReadHandler.cpp

@@ -49,16 +49,16 @@ CHIP_ERROR ReadHandler::Init(Messaging::ExchangeManager * apExchangeMgr, Interac
  mCurrentPriority = PriorityLevel::Invalid;
  mIsPrimingReports = true;
  MoveToState(HandlerState::Initialized);
- mpDelegate = apDelegate;
- mSubscriptionId = 0;
- mHoldReport = false;
- mDirty = false;
- mActiveSubscription = false;
- mIsChunkedReport = false;
- mInteractionType = aInteractionType;
- mInitiatorNodeId = apExchangeContext->GetSessionHandle().GetPeerNodeId();
- mFabricIndex = apExchangeContext->GetSessionHandle().GetFabricIndex();
-
+ mpDelegate  = apDelegate;
+ mSubscriptionId  = 0;
+ mHoldReport  = false;
+ mDirty  = false;
+ mActiveSubscription  = false;
+ mIsChunkedReport  = false;
+ mInteractionType  = aInteractionType;
+ mInitiatorNodeId  = apExchangeContext->GetSessionHandle().GetPeerNodeId();
+ mFabricIndex  = apExchangeContext->GetSessionHandle().GetFabricIndex();
+ mNeedRefreshSubscribe = false;
  if (apExchangeContext != nullptr)
  {
  apExchangeContext->SetDelegate(this);
@@ -110,6 +110,7 @@ void ReadHandler::Shutdown(ShutdownOptions aOptions)
  mActiveSubscription = false;
  mIsChunkedReport = false;
  mInitiatorNodeId = kUndefinedNodeId;
+ mNeedRefreshSubscribe = false;
 }
 
 CHIP_ERROR ReadHandler::OnReadInitialRequest(System::PacketBufferHandle && aPayload)
@@ -637,6 +638,9 @@ void ReadHandler::OnUnblockHoldReportCallback(System::Layer * apSystemLayer, voi
 void ReadHandler::OnRefreshSubscribeTimerSyncCallback(System::Layer * apSystemLayer, void * apAppState)
 {
  VerifyOrReturn(apAppState != nullptr);
+ ReadHandler * readHandler = static_cast<ReadHandler *>(apAppState);
+ readHandler->mNeedRefreshSubscribe = true;
+ ChipLogProgress(DataManagement, "Refresh subscribe timer sync after max %d seconds", readHandler->mMaxIntervalFloorSeconds);
  InteractionModelEngine::GetInstance()->GetReportingEngine().ScheduleRun();
 }
 
@@ -647,7 +651,8 @@ CHIP_ERROR ReadHandler::RefreshSubscribeSyncTimer()
  OnUnblockHoldReportCallback, this);
  InteractionModelEngine::GetInstance()->GetExchangeManager()->GetSessionManager()->SystemLayer()->CancelTimer(
  OnRefreshSubscribeTimerSyncCallback, this);
- mHoldReport = true;
+ mHoldReport = true;
+ mNeedRefreshSubscribe = false;
  ReturnErrorOnFailure(
  InteractionModelEngine::GetInstance()->GetExchangeManager()->GetSessionManager()->SystemLayer()->StartTimer(
  System::Clock::Seconds16(mMinIntervalFloorSeconds), OnUnblockHoldReportCallback, this));

src/app/ReadHandler.h

@@ -107,7 +107,10 @@ class ReadHandler : public Messaging::ExchangeDelegate
  CHIP_ERROR SendReportData(System::PacketBufferHandle && aPayload, bool mMoreChunks);
 
  bool IsFree() const { return mState == HandlerState::Uninitialized; }
- bool IsReportable() const { return mState == HandlerState::GeneratingReports && !mHoldReport; }
+ bool IsReportable() const
+ {
+ return mState == HandlerState::GeneratingReports && !mHoldReport && (mDirty || mNeedRefreshSubscribe);
+ }
  bool IsGeneratingReports() const { return mState == HandlerState::GeneratingReports; }
  bool IsAwaitingReportResponse() const { return mState == HandlerState::AwaitingReportResponse; }
  virtual ~ReadHandler() = default;
@@ -214,6 +217,7 @@ class ReadHandler : public Messaging::ExchangeDelegate
  FabricIndex mFabricIndex = 0;
  AttributePathExpandIterator mAttributePathExpandIterator = AttributePathExpandIterator(nullptr);
  bool mIsFabricFiltered = false;
+ bool mNeedRefreshSubscribe = false;
 };
 } // namespace app
 } // namespace chip