04/05: daemon: Set TCP_NODELAY and TCP_QUICKACK on remote sockets.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit 6efb578a1412bae959dd6b1755e2c333eb4e4cd8
Author: Ludovic Courtès <address@hidden>
Date:   Thu Jun 22 10:56:18 2017 +0200

    daemon: Set TCP_NODELAY and TCP_QUICKACK on remote sockets.
    
    * nix/nix-daemon/nix-daemon.cc (acceptConnection): Set TCP_NODELAY and
    TCP_QUICKACK on REMOTE.
---
 nix/nix-daemon/nix-daemon.cc | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc
index 3d8e909..b20225b 100644
--- a/nix/nix-daemon/nix-daemon.cc
+++ b/nix/nix-daemon/nix-daemon.cc
@@ -19,6 +19,9 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <arpa/inet.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+
 #include <fcntl.h>
 #include <errno.h>
 #include <pwd.h>
@@ -839,6 +842,21 @@ static void acceptConnection(int fdSocket)
 
        closeOnExec(remote);
 
+       {
+         int enabled = 1;
+
+         /* If we're on a TCP connection, disable Nagle's algorithm so that
+            data is sent as soon as possible.  */
+         (void) setsockopt(remote, SOL_TCP, TCP_NODELAY,
+                           &enabled, sizeof enabled);
+
+#if defined(TCP_QUICKACK)
+         /* Enable TCP quick-ack if applicable; this might help a little.  */
+         (void) setsockopt(remote, SOL_TCP, TCP_QUICKACK,
+                           &enabled, sizeof enabled);
+#endif
+       }
+
        pid_t clientPid = -1;
        bool trusted = false;