From a4e28b3d1e5c95eb0c87f144851cd65048c3e0bc Mon Sep 17 00:00:00 2001 From: Gregory Maxwell Date: Wed, 21 Oct 2015 23:52:29 +0000 Subject: Set TCP_NODELAY on P2P sockets. Nagle appears to be a significant contributor to latency now that the static sleeps are gone. Most of our messages are relatively large compared to IP + TCP so I do not expect this to create enormous overhead. This may also reduce traffic burstyness somewhat. --- src/net.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'src/net.cpp') diff --git a/src/net.cpp b/src/net.cpp index 87c4f0af0..58b946f4a 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -963,6 +963,15 @@ static void AcceptConnection(const ListenSocket& hListenSocket) { return; } + // According to the internet TCP_NODELAY is not carried into accepted sockets + // on all platforms. Set it again here just to be sure. + int set = 1; +#ifdef WIN32 + setsockopt(hSocket, IPPROTO_TCP, TCP_NODELAY, (const char*)&set, sizeof(int)); +#else + setsockopt(hSocket, IPPROTO_TCP, TCP_NODELAY, (void*)&set, sizeof(int)); +#endif + if (CNode::IsBanned(addr) && !whitelisted) { LogPrintf("connection from %s dropped (banned)\n", addr.ToString()); @@ -1790,8 +1799,11 @@ bool BindListenPort(const CService &addrBind, string& strError, bool fWhiteliste // Allow binding if the port is still in TIME_WAIT state after // the program was closed and restarted. setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (void*)&nOne, sizeof(int)); + // Disable Nagle's algorithm + setsockopt(hListenSocket, IPPROTO_TCP, TCP_NODELAY, (void*)&nOne, sizeof(int)); #else setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (const char*)&nOne, sizeof(int)); + setsockopt(hListenSocket, IPPROTO_TCP, TCP_NODELAY, (const char*)&nOne, sizeof(int)); #endif // Set to non-blocking, incoming connections will also inherit this -- cgit v1.2.3