Attachment 81218 Details for Bug 116335 – patch-1.diff

[patch] patch-1.diff

patch-1.diff (text/plain), 2.68 KB, created by Andre Oppermann on 2010-08-16 22:27:15 UTC

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Creator: Andre Oppermann

Created: 2010-08-16 22:27:15 UTC

Size: 2.68 KB

patch

obsolete

>Index: tcp_output.c
>===================================================================
>--- tcp_output.c	(revision 211396)
>+++ tcp_output.c	(working copy)
>@@ -543,29 +543,53 @@
> 	}
> 
> 	/*
>-	 * Compare available window to amount of window
>-	 * known to peer (as advertised window less
>-	 * next expected input).  If the difference is at least two
>-	 * max size segments, or at least 50% of the maximum possible
>-	 * window, then want to send a window update to peer.
>-	 * Skip this if the connection is in T/TCP half-open state.
>-	 * Don't send pure window updates when the peer has closed
>-	 * the connection and won't ever send more data.
>+	 * Sending of standalone window updates.
>+	 *
>+	 * Window updates important when we close our window
>+	 * due to a full socket buffer and are opening it again
>+	 * after the application reads data from it.  Once the
>+	 * window has opened again and the remote end starts to
>+	 * send again the ACK clock takes over and provides the
>+	 * most current window information.
>+	 *
>+	 * We must avoid to the silly window syndrome whereas
>+	 * every read from the receive buffer, no matter how
>+	 * small, causes a window update to be sent. We also
>+	 * should avoid sending a flurry of window updates when
>+	 * the socket buffer had queued a lot of data and the
>+	 * application is doing small reads.
>+	 *
>+	 * Don't send an independent window update if a delayed
>+	 * ACK is pending (it will get piggy-backed on it) or the
>+	 * remote side already has done a half-close and won't send
>+	 * more data.  Skip this if the connection is in T/TCP
>+	 * half-open state.
> 	 */
> 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
>+	    !(tp->t_flags & TF_DELACK) &&
> 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
> 		/*
> 		 * "adv" is the amount we can increase the window,
> 		 * taking into account that we are limited by
> 		 * TCP_MAXWIN << tp->rcv_scale.
> 		 */
>-		long adv = min(recwin, (long)TCP_MAXWIN << tp->rcv_scale) -
>-			(tp->rcv_adv - tp->rcv_nxt);
>+		u_int adv = min(recwin, ((u_int)TCP_MAXWIN << tp->rcv_scale) -
>+			(tp->rcv_adv - tp->rcv_nxt));
> 
>-		if (adv >= (long) (2 * tp->t_maxseg))
>+		/*
>+		 * Send an update when we can increase by more than
>+		 * 1/4th of the socket buffer capacity.
>+		 * When the buffer is getting full or is very small
>+		 * be more aggressive and send an update whenever
>+		 * we can increase by two mss sized segments.
>+		 * In all other situations the ACK's to new incoming
>+		 * data will carry further increases.
>+		 */
>+		if (adv >= 2 * tp->t_maxseg &&
>+		    (adv >= so->so_rcv.sb_hiwat / 4 ||
>+		     recwin <= so->so_rcv.sb_hiwat / 8 ||
>+		     so->so_rcv.sb_hiwat <= 8 * tp->t_maxopd))
> 			goto send;
>-		if (2 * adv >= (long) so->so_rcv.sb_hiwat)
>-			goto send;
> 	}
> 
> 	/*

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