From 5e88acf21727deabb4323110f209752f119e2d3f Mon Sep 17 00:00:00 2001
From: Thilo Schulz <arny@ats.s.bawue.de>
Date: Fri, 18 Aug 2006 01:50:51 +0000
Subject: [PATCH] Fix 100% CPU usage on idle dedicated servers.

---
 code/qcommon/common.c |  4 ++--
 code/server/sv_main.c | 10 +++++++++-
 code/unix/unix_net.c  | 33 +++++++++++++++++++++++++++------
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/code/qcommon/common.c b/code/qcommon/common.c
index d1d40a92..e861b516 100644
--- a/code/qcommon/common.c
+++ b/code/qcommon/common.c
@@ -2660,9 +2660,9 @@ int Com_ModifyMsec( int msec ) {
 		// dedicated servers don't want to clamp for a much longer
 		// period, because it would mess up all the client's views
 		// of time.
-		if ( msec > 500 ) {
+		if (com_sv_running->integer && msec > 500)
 			Com_Printf( "Hitch warning: %i msec frame time\n", msec );
-		}
+
 		clampTime = 5000;
 	} else 
 	if ( !com_sv_running->integer ) {
diff --git a/code/server/sv_main.c b/code/server/sv_main.c
index c2ae7102..152ecbdb 100644
--- a/code/server/sv_main.c
+++ b/code/server/sv_main.c
@@ -777,7 +777,15 @@ void SV_Frame( int msec ) {
 		return;
 	}
 
-	if ( !com_sv_running->integer ) {
+	if (!com_sv_running->integer)
+	{
+		if(com_dedicated->integer)
+		{
+			// Block indefinitely until something interesting happens
+			// on STDIN.
+			NET_Sleep(-1);
+		}
+		
 		return;
 	}
 
diff --git a/code/unix/unix_net.c b/code/unix/unix_net.c
index 73c0fd65..12908eba 100644
--- a/code/unix/unix_net.c
+++ b/code/unix/unix_net.c
@@ -648,19 +648,40 @@ char *NET_ErrorString (void)
 // sleeps msec or until net socket is ready
 void NET_Sleep(int msec)
 {
-    struct timeval timeout;
+	struct timeval timeout;
 	fd_set	fdset;
 	extern qboolean stdin_active;
+	qboolean not_empty = qfalse;
 
-	if (!ip_socket || !com_dedicated->integer)
+	if (!com_dedicated->integer)
 		return; // we're not a server, just run full speed
 
 	FD_ZERO(&fdset);
 	if (stdin_active)
+	{
 		FD_SET(0, &fdset); // stdin is processed too
-	FD_SET(ip_socket, &fdset); // network socket
-	timeout.tv_sec = msec/1000;
-	timeout.tv_usec = (msec%1000)*1000;
-	select(ip_socket+1, &fdset, NULL, NULL, &timeout);
+		not_empty = qtrue;
+	}
+	if(ip_socket && com_sv_running->integer)
+	{
+		FD_SET(ip_socket, &fdset); // network socket
+		not_empty = qtrue;
+	}
+	
+	// There's no reason to call select() with an empty set.
+	if(not_empty)
+	{
+		if(msec >= 0)
+		{
+			timeout.tv_sec = msec/1000;
+			timeout.tv_usec = (msec%1000)*1000;
+			select(ip_socket+1, &fdset, NULL, NULL, &timeout);
+		}
+		else
+		{
+			// Block indefinitely
+			select(ip_socket+1, &fdset, NULL, NULL, NULL);
+		}
+	}
 }