From: "David S. Miller" <davem@davemloft.net>
To: rick.jones2@hp.com
Cc: netdev@vger.kernel.org, rdreier@cisco.com,
linux-kernel@vger.kernel.org, openib-general@openib.org
Subject: Re: TSO and IPoIB performance degradation
Date: Thu, 09 Mar 2006 23:23:01 -0800 (PST) [thread overview]
Message-ID: <20060309.232301.77550306.davem@davemloft.net> (raw)
In-Reply-To: <4410C671.2050300@hp.com>
From: Rick Jones <rick.jones2@hp.com>
Date: Thu, 09 Mar 2006 16:21:05 -0800
> well, there are stacks which do "stretch acks" (after a fashion) that
> make sure when they see packet loss to "do the right thing" wrt sending
> enough acks to allow cwnds to open again in a timely fashion.
Once a loss happens, it's too late to stop doing the stretch ACKs, the
damage is done already. It is going to take you at least one
extra RTT to recover from the loss compared to if you were not doing
stretch ACKs.
You have to keep giving consistent well spaced ACKs back to the
receiver in order to recover from loss optimally.
The ACK every 2 full sized frames behavior of TCP is absolutely
essential.
next prev parent reply other threads:[~2006-03-10 7:23 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-06 22:34 TSO and IPoIB performance degradation Michael S. Tsirkin
2006-03-06 22:40 ` David S. Miller
2006-03-06 22:50 ` Stephen Hemminger
2006-03-07 3:13 ` Shirley Ma
2006-03-07 21:44 ` Matt Leininger
2006-03-07 21:49 ` Stephen Hemminger
2006-03-07 21:53 ` Michael S. Tsirkin
2006-03-08 0:11 ` Matt Leininger
2006-03-08 0:18 ` David S. Miller
2006-03-08 1:17 ` Roland Dreier
2006-03-08 1:23 ` David S. Miller
2006-03-08 1:34 ` Roland Dreier
2006-03-08 12:53 ` Michael S. Tsirkin
2006-03-08 20:53 ` David S. Miller
2006-03-09 23:48 ` David S. Miller
2006-03-10 0:10 ` Michael S. Tsirkin
2006-03-10 0:38 ` Michael S. Tsirkin
2006-03-10 7:18 ` David S. Miller
2006-03-10 0:21 ` Rick Jones
2006-03-10 7:23 ` David S. Miller [this message]
2006-03-10 17:44 ` Rick Jones
2006-03-20 9:06 ` Michael S. Tsirkin
2006-03-20 9:55 ` David S. Miller
2006-03-20 10:22 ` Michael S. Tsirkin
2006-03-20 10:37 ` David S. Miller
2006-03-20 11:27 ` Michael S. Tsirkin
2006-03-20 11:47 ` Arjan van de Ven
2006-03-20 11:49 ` Lennert Buytenhek
2006-03-20 11:53 ` Arjan van de Ven
2006-03-20 13:35 ` Michael S. Tsirkin
2006-03-20 12:04 ` Michael S. Tsirkin
2006-03-20 15:09 ` Benjamin LaHaise
2006-03-20 18:58 ` Rick Jones
2006-03-20 23:00 ` David S. Miller
2006-04-27 4:13 ` Troy Benjegerdes
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