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engine/net_ws_queued_packet_sender.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+#include "net_ws_headers.h"
+#include "net_ws_queued_packet_sender.h"
+
+#include "tier1/utlvector.h"
+#include "tier1/utlpriorityqueue.h"
+
+#include "tier0/etwprof.h"
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+ConVar net_queued_packet_thread( "net_queued_packet_thread", "1", 0, "Use a high priority thread to send queued packets out instead of sending them each frame." );
+ConVar net_queue_trace( "net_queue_trace", "0", 0 );
+
+class CQueuedPacketSender : public CThread, public IQueuedPacketSender
+{
+public:
+	CQueuedPacketSender();
+	~CQueuedPacketSender();
+
+	// IQueuedPacketSender
+
+	virtual bool Setup();
+	virtual void Shutdown();
+	virtual bool IsRunning() { return CThread::IsAlive(); }
+
+	virtual void ClearQueuedPacketsForChannel( INetChannel *pChan );
+	virtual void QueuePacket( INetChannel *pChan, SOCKET s, const char FAR *buf, int len, const struct sockaddr FAR * to, int tolen, uint32 msecDelay );
+	virtual bool HasQueuedPackets( const INetChannel *pChan ) const;
+private:
+
+	// CThread Overrides
+	virtual bool Start( unsigned int nBytesStack = 0 );
+	virtual int Run();
+
+private:
+
+	class CQueuedPacket
+	{
+	public:
+		uint32				m_unSendTime;
+		const void 			*m_pChannel;  // We don't actually use the channel
+		SOCKET				m_Socket;
+		CUtlVector<char>	to;	// sockaddr
+		CUtlVector<char>	buf;
+
+		// We want the list sorted in ascending order, so note that we return > rather than <
+		static bool LessFunc( CQueuedPacket * const &lhs, CQueuedPacket * const &rhs )
+		{
+			return lhs->m_unSendTime > rhs->m_unSendTime;
+		}
+	};
+
+	CUtlPriorityQueue< CQueuedPacket * > m_QueuedPackets;
+	CThreadMutex m_QueuedPacketsCS;
+	CThreadEvent m_hThreadEvent;
+	volatile bool m_bThreadShouldExit;
+};
+
+static CQueuedPacketSender g_QueuedPacketSender;
+IQueuedPacketSender *g_pQueuedPackedSender = &g_QueuedPacketSender;
+
+
+CQueuedPacketSender::CQueuedPacketSender() :
+	m_QueuedPackets( 0, 0, CQueuedPacket::LessFunc )
+{
+	SetName( "QueuedPacketSender" );
+	m_bThreadShouldExit = false;
+}
+
+CQueuedPacketSender::~CQueuedPacketSender()
+{
+	Shutdown();
+}
+
+bool CQueuedPacketSender::Setup()
+{
+	return Start();
+}
+
+bool CQueuedPacketSender::Start( unsigned nBytesStack )
+{
+	Shutdown();
+
+	if ( CThread::Start( nBytesStack ) )
+	{
+		// Ahhh the perfect cross-platformness of the threads library.
+#ifdef IS_WINDOWS_PC
+		SetPriority( THREAD_PRIORITY_HIGHEST );
+#elif POSIX
+		//SetPriority( PRIORITY_MAX );
+#endif
+		m_bThreadShouldExit = false;
+		return true;
+	}
+	else
+	{
+		return false;
+	}
+}
+
+void CQueuedPacketSender::Shutdown()
+{
+	if ( !IsAlive() )
+		return;
+		
+	m_bThreadShouldExit = true;
+	m_hThreadEvent.Set();
+	
+	Join(); // Wait for the thread to exit.
+
+	while ( m_QueuedPackets.Count() > 0 )
+	{
+		delete m_QueuedPackets.ElementAtHead();
+		m_QueuedPackets.RemoveAtHead();
+	}
+	m_QueuedPackets.Purge();
+}
+
+void CQueuedPacketSender::ClearQueuedPacketsForChannel( INetChannel *pChan )
+{
+	AUTO_LOCK( m_QueuedPacketsCS );
+
+	for ( int i = m_QueuedPackets.Count()-1; i >= 0; i-- )
+	{
+		CQueuedPacket *p = m_QueuedPackets.Element( i );
+		if ( p->m_pChannel == pChan )
+		{
+			m_QueuedPackets.RemoveAt( i );
+			delete p;
+		}
+	}
+}
+
+bool CQueuedPacketSender::HasQueuedPackets( const INetChannel *pChan ) const
+{
+	AUTO_LOCK( m_QueuedPacketsCS );
+
+	for ( int i = 0; i < m_QueuedPackets.Count(); ++i )
+	{
+		const CQueuedPacket *p = m_QueuedPackets.Element( i );
+		if ( p->m_pChannel == pChan )
+		{
+			return true;
+		}
+	}
+
+	return false;
+}
+void CQueuedPacketSender::QueuePacket( INetChannel *pChan, SOCKET s, const char FAR *buf, int len, const struct sockaddr FAR * to, int tolen, uint32 msecDelay )
+{
+	AUTO_LOCK( m_QueuedPacketsCS );
+
+	// We'll pull all packets we should have sent by now and send them out right away
+	uint32 msNow = Plat_MSTime();
+
+	int nMaxQueuedPackets = 1024;
+	if ( m_QueuedPackets.Count() < nMaxQueuedPackets )
+	{
+		// Add this packet to the queue.
+		CQueuedPacket *pPacket = new CQueuedPacket;
+		pPacket->m_unSendTime = msNow + msecDelay;
+		pPacket->m_Socket = s;
+		pPacket->m_pChannel = pChan;
+		pPacket->buf.CopyArray( (char*)buf, len );
+		pPacket->to.CopyArray( (char*)to, tolen );
+		m_QueuedPackets.Insert( pPacket );
+	}
+	else
+	{
+		static int nWarnings = 5;
+		if ( --nWarnings > 0 )
+		{
+			Warning( "CQueuedPacketSender: num queued packets >= nMaxQueuedPackets. Not queueing anymore.\n" );
+		}
+	}
+
+	// Tell the thread that we have a queued packet.
+	m_hThreadEvent.Set();
+}
+
+extern int NET_SendToImpl( SOCKET s, const char FAR * buf, int len, const struct sockaddr FAR * to, int tolen, int iGameDataLength );
+
+int CQueuedPacketSender::Run()
+{
+	 // Normally TT_INFINITE but we wakeup every 50ms just in case.
+	uint32 waitIntervalNoPackets = 50;
+	uint32 waitInterval = waitIntervalNoPackets;
+	while ( 1 )
+	{
+		if ( m_hThreadEvent.Wait( waitInterval ) )
+		{
+			// Someone signaled the thread. Either we're being told to exit or 
+			// we're being told that a packet was just queued.
+			if ( m_bThreadShouldExit )
+				return 0;
+		}
+
+		// Assume nothing to do and that we'll sleep again
+		waitInterval = waitIntervalNoPackets;
+
+		// OK, now send a packet.
+		{
+			AUTO_LOCK( m_QueuedPacketsCS );
+		
+			// We'll pull all packets we should have sent by now and send them out right away
+			uint32 msNow = Plat_MSTime();
+
+			bool bTrace = net_queue_trace.GetInt() == NET_QUEUED_PACKET_THREAD_DEBUG_VALUE;
+
+			while ( m_QueuedPackets.Count() > 0 )
+			{
+				CQueuedPacket *pPacket = m_QueuedPackets.ElementAtHead();
+				if ( pPacket->m_unSendTime > msNow )
+				{
+					// Sleep until next we need this packet
+					waitInterval = pPacket->m_unSendTime - msNow;
+					// Emit ETW events to help with diagnosing network throttling issues as
+					// these often have a severe effect on load times in Dota.
+					ETWMark1I( "CQueuedPacketSender::Run sleeping (ms)", waitInterval );
+					if ( bTrace )
+					{
+						Warning( "SQ:  sleeping for %u msecs at %f\n", waitInterval, Plat_FloatTime() );
+					}
+					break;
+				}
+
+				// If it's a bot, don't do anything. Note: we DO want this code deep here because bots only
+				// try to send packets when sv_stressbots is set, in which case we want it to act as closely
+				// as a real player as possible.
+				sockaddr_in *pInternetAddr = (sockaddr_in*)pPacket->to.Base();
+			#ifdef _WIN32
+				if ( pInternetAddr->sin_addr.S_un.S_addr != 0
+			#else
+				if ( pInternetAddr->sin_addr.s_addr != 0 
+			#endif
+					&& pInternetAddr->sin_port != 0 )
+				{		
+					if ( bTrace )
+					{
+						Warning( "SQ:  sending %d bytes at %f\n", pPacket->buf.Count(), Plat_FloatTime() );
+					}
+
+					NET_SendToImpl
+					( 
+						pPacket->m_Socket, 
+						pPacket->buf.Base(), 
+						pPacket->buf.Count(), 
+						(sockaddr*)pPacket->to.Base(),
+						pPacket->to.Count(), 
+						-1 
+					);
+				}	
+				
+				delete pPacket;
+				m_QueuedPackets.RemoveAtHead();
+			}
+		}
+	}
+}
+