last packet optimization (#3363)

* last packet optimization

* comment

* test

* missed one

* set tcp mss

firmware/console/binary/tunerstudio_io.cpp

@@ -45,7 +45,7 @@ void TsChannelBase::writeCrcPacketSmall(uint8_t responseCode, const uint8_t* buf
 	*reinterpret_cast<uint32_t*>(&scratchBuffer[size + 3]) = SWAP_UINT32(crc);
 
 	// Write to the underlying stream
-	write(reinterpret_cast<uint8_t*>(scratchBuffer), size + 7);
+	write(reinterpret_cast<uint8_t*>(scratchBuffer), size + 7, true);
 }
 
 void TsChannelBase::writeCrcPacketLarge(uint8_t responseCode, const uint8_t* buf, size_t size) {
@@ -62,15 +62,15 @@ void TsChannelBase::writeCrcPacketLarge(uint8_t responseCode, const uint8_t* buf
 	*(uint32_t*)crcBuffer = SWAP_UINT32(crc);
 
 	// Write header
-	write(headerBuffer, sizeof(headerBuffer));
+	write(headerBuffer, sizeof(headerBuffer), false);
 
 	// If data, write that
 	if (size) {
-		write(buf, size);
+		write(buf, size, false);
 	}
 
 	// Lastly the CRC footer
-	write(crcBuffer, sizeof(crcBuffer));
+	write(crcBuffer, sizeof(crcBuffer), true);
 }
 
 TsChannelBase::TsChannelBase(const char *name) {
@@ -101,7 +101,7 @@ void TsChannelBase::sendResponse(ts_response_format_e mode, const uint8_t * buff
 		writeCrcPacket(TS_RESPONSE_OK, buffer, size);
 	} else {
 		if (size > 0) {
-			write(buffer, size);
+			write(buffer, size, true);
 			flush();
 		}
 	}

firmware/console/binary/tunerstudio_io.h

@@ -38,7 +38,7 @@ class TsChannelBase {
 public:
 	TsChannelBase(const char *name);
 	// Virtual functions - implement these for your underlying transport
-	virtual void write(const uint8_t* buffer, size_t size) = 0;
+	virtual void write(const uint8_t* buffer, size_t size, bool isEndOfPacket = false) = 0;
 	virtual size_t readTimeout(uint8_t* buffer, size_t size, int timeout) = 0;
 
 	// These functions are optional to implement, not all channels need them
@@ -84,7 +84,7 @@ public:
 	void start(uint32_t baud) override;
 	void stop() override;
 
-	void write(const uint8_t* buffer, size_t size) override;
+	void write(const uint8_t* buffer, size_t size, bool isEndOfPacket) override;
 	size_t readTimeout(uint8_t* buffer, size_t size, int timeout) override;
 
 private:
@@ -101,7 +101,7 @@ public:
 	void start(uint32_t baud) override;
 	void stop() override;
 
-	void write(const uint8_t* buffer, size_t size) override;
+	void write(const uint8_t* buffer, size_t size, bool isEndOfPacket) override;
 	size_t readTimeout(uint8_t* buffer, size_t size, int timeout) override;
 
 protected:

firmware/console/binary/tunerstudio_io_serial.cpp

@@ -23,7 +23,7 @@ void SerialTsChannel::stop() {
 	sdStop(m_driver);
 }
 
-void SerialTsChannel::write(const uint8_t* buffer, size_t size) {
+void SerialTsChannel::write(const uint8_t* buffer, size_t size, bool) {
 	chnWriteTimeout(m_driver, buffer, size, BINARY_IO_TIMEOUT);
 }
 
@@ -56,7 +56,7 @@ void UartTsChannel::stop() {
 	uartStop(m_driver);
 }
 
-void UartTsChannel::write(const uint8_t* buffer, size_t size) {
+void UartTsChannel::write(const uint8_t* buffer, size_t size, bool) {
 	uartSendTimeout(m_driver, &size, buffer, BINARY_IO_TIMEOUT);
 }
 

firmware/console/ethernet_console.cpp

@@ -36,8 +36,11 @@ public:
 		return connectionSocket != -1;
 	}
 
-	void write(const uint8_t* buffer, size_t size) override {
-		lwip_send(connectionSocket, buffer, size, /*flags =*/ 0);
+	void write(const uint8_t* buffer, size_t size, bool isEndOfPacket) override {
+		// If not the end of a packet, set the MSG_MORE flag to indicate to the transport
+		// that we have more to add to the buffer before queuing a flush.
+		auto flags = isEndOfPacket ? 0 : MSG_MORE;
+		lwip_send(connectionSocket, buffer, size, flags);
 	}
 
 	size_t readTimeout(uint8_t* buffer, size_t size, int /*timeout*/) override {

firmware/console/lwipopts.h

@@ -76,4 +76,9 @@
 #define LWIP_ETHADDR_4 0x34
 #define LWIP_ETHADDR_5 0x56
 
+#include "rusefi_generated.h"
+
+// Ensure that one TCP segment can always fit an entire response to TS - we never need to split a TS packet across multiple frames.
+#define TCP_MSS (BLOCKING_FACTOR + 10)
+
 #endif /* LWIP_HDR_LWIPOPTS_H__ */

firmware/console/usb_console.cpp

@@ -23,7 +23,7 @@ public:
 		return is_usb_serial_ready();
 	}
 
-	void write(const uint8_t* buffer, size_t size) override {
+	void write(const uint8_t* buffer, size_t size, bool) override {
 		chnWriteTimeout(m_channel, buffer, size, BINARY_IO_TIMEOUT);
 	}
 

unit_tests/tests/test_tunerstudio.cpp

@@ -7,7 +7,7 @@ class MockTsChannel : public TsChannelBase {
 public:
 	MockTsChannel() : TsChannelBase("Test") { }
 
-	void write(const uint8_t* buffer, size_t size) override {
+	void write(const uint8_t* buffer, size_t size, bool /*isLastWriteInTransaction*/) override {
 		memcpy(&st5TestBuffer[writeIdx], buffer, size);
 		writeIdx += size;
 	}