From: "Michael S. Tsirkin" <mst@mellanox.co.il>
To: "David S. Miller" <davem@davemloft.net>
Cc: rick.jones2@hp.com, netdev@vger.kernel.org, rdreier@cisco.com,
linux-kernel@vger.kernel.org, openib-general@openib.org
Subject: Re: TSO and IPoIB performance degradation
Date: Mon, 20 Mar 2006 12:22:34 +0200 [thread overview]
Message-ID: <20060320102234.GV29929@mellanox.co.il> (raw)
In-Reply-To: <20060320.015500.72136710.davem@davemloft.net>
Quoting r. David S. Miller <davem@davemloft.net>:
> The path an SKB can take is opaque and unknown until the very last
> moment it is actually given to the device transmit function.
Why, I was proposing looking at dst cache. If that's NULL, well,
we won't stretch ACKs. Worst case we apply the wrong optimization.
Right?
> People need to get the "special case this topology" ideas out of their
> heads. :-)
Okay, I get that.
What I'd like to clarify, however: rfc2581 explicitly states that in some cases
it might be OK to generate ACKs less frequently than every second full-sized
segment. Given Matt's measurements, TCP on top of IP over InfiniBand on Linux
seems to hit one of these cases. Do you agree to that?
--
Michael S. Tsirkin
Staff Engineer, Mellanox Technologies
next prev parent reply other threads:[~2006-03-20 10:21 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <OF336D72E6.999D2A30-ON8725712A.00117C92-8825712A.00116629@us.ibm.com>
2006-03-07 21:44 ` [openib-general] " 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
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 [this message]
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
2006-03-06 22:34 Michael S. Tsirkin
2006-03-06 22:40 ` David S. Miller
2006-03-06 22:50 ` Stephen Hemminger
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