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.
This commit is contained in:
Gregory Maxwell 2015-10-21 23:52:29 +00:00
parent 0fbfc5106c
commit a4e28b3d1e
3 changed files with 21 additions and 1 deletions

View file

@ -38,6 +38,7 @@
#include <sys/types.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <limits.h>

View file

@ -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

View file

@ -444,12 +444,19 @@ bool static ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRe
if (hSocket == INVALID_SOCKET)
return false;
#ifdef SO_NOSIGPIPE
int set = 1;
#ifdef SO_NOSIGPIPE
// Different way of disabling SIGPIPE on BSD
setsockopt(hSocket, SOL_SOCKET, SO_NOSIGPIPE, (void*)&set, sizeof(int));
#endif
//Disable Nagle's algorithm
#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
// Set to non-blocking
if (!SetSocketNonBlocking(hSocket, true))
return error("ConnectSocketDirectly: Setting socket to non-blocking failed, error %s\n", NetworkErrorString(WSAGetLastError()));