From 3ae6928d8d3bfb909b72b80e8aaf043325959c4b Mon Sep 17 00:00:00 2001
From: David Turner <digit@android.com>
Date: Tue, 16 Aug 2011 00:55:43 +0200
Subject: [PATCH] emulator opengles: improve TcpStream throughput

This patch improves the performance of the TcpStream implementation
on the host by disabling the Nagle algorithm, thus improving the
bandwidth of small packets.

When used with the corresponding change in the emulator, this
significantly improves the speed of OpenGLES emulation for many
applications.

Change-Id: Ic09e51ecddf04bc7d667f46e1d260030d5fcad88
---
 .../opengl/shared/OpenglCodecCommon/TcpStream.cpp    | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/emulator/opengl/shared/OpenglCodecCommon/TcpStream.cpp b/tools/emulator/opengl/shared/OpenglCodecCommon/TcpStream.cpp
index 4e947daa5..c057ff991 100644
--- a/tools/emulator/opengl/shared/OpenglCodecCommon/TcpStream.cpp
+++ b/tools/emulator/opengl/shared/OpenglCodecCommon/TcpStream.cpp
@@ -23,6 +23,9 @@
 
 #ifndef _WIN32
 #include <netinet/in.h>
+#include <netinet/tcp.h>
+#else
+#include <ws2tcpip.h>
 #endif
 
 TcpStream::TcpStream(size_t bufSize) :
@@ -39,6 +42,15 @@ TcpStream::TcpStream(int sock, size_t bufSize) :
     m_bufsize(bufSize),
     m_buf(NULL)
 {
+    // disable Nagle algorithm to improve bandwidth of small
+    // packets which are quite common in our implementation.
+#ifdef _WIN32
+    DWORD  flag;
+#else
+    int    flag;
+#endif
+    flag = 1;
+    setsockopt( sock, IPPROTO_TCP, TCP_NODELAY, (const char*)&flag, sizeof(flag) );
 }
 
 TcpStream::~TcpStream()