From: Benjamin LaHaise <bcrl@kvack.org>
To: "Michael S. Tsirkin" <mst@mellanox.co.il>
Cc: Lennert Buytenhek <buytenh@wantstofly.org>,
Arjan van de Ven <arjan@infradead.org>,
"David S. Miller" <davem@davemloft.net>,
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 10:09:42 -0500 [thread overview]
Message-ID: <20060320150941.GD16108@kvack.org> (raw)
In-Reply-To: <20060320120407.GY29929@mellanox.co.il>
On Mon, Mar 20, 2006 at 02:04:07PM +0200, Michael S. Tsirkin wrote:
> does not stretch ACKs anymore. RFC 2581 does mention that it might be OK to
> stretch ACKs "after careful consideration", and we are seeing that it helps
> IP over InfiniBand, so recent Linux kernels perform worse in that respect.
>
> And since there does not seem to be a way to figure it out automagically when
> doing this is a good idea, I proposed adding some kind of knob that will let the
> user apply the consideration for us.
Wouldn't it make sense to strech the ACK when the previous ACK is still in
the TX queue of the device? I know that sort of behaviour was always an
issue on modem links where you don't want to send out redundant ACKs.
-ben
--
"Time is of no importance, Mr. President, only life is important."
Don't Email: <dont@kvack.org>.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin LaHaise <bcrl@kvack.org>
To: "Michael S. Tsirkin" <mst@mellanox.co.il>
Cc: netdev@vger.kernel.org, rdreier@cisco.com, rick.jones2@hp.com,
linux-kernel@vger.kernel.org, openib-general@openib.org,
"David S. Miller" <davem@davemloft.net>,
Lennert Buytenhek <buytenh@wantstofly.org>,
Arjan van de Ven <arjan@infradead.org>
Subject: Re: TSO and IPoIB performance degradation
Date: Mon, 20 Mar 2006 10:09:42 -0500 [thread overview]
Message-ID: <20060320150941.GD16108@kvack.org> (raw)
In-Reply-To: <20060320120407.GY29929@mellanox.co.il>
On Mon, Mar 20, 2006 at 02:04:07PM +0200, Michael S. Tsirkin wrote:
> does not stretch ACKs anymore. RFC 2581 does mention that it might be OK to
> stretch ACKs "after careful consideration", and we are seeing that it helps
> IP over InfiniBand, so recent Linux kernels perform worse in that respect.
>
> And since there does not seem to be a way to figure it out automagically when
> doing this is a good idea, I proposed adding some kind of knob that will let the
> user apply the consideration for us.
Wouldn't it make sense to strech the ACK when the previous ACK is still in
the TX queue of the device? I know that sort of behaviour was always an
issue on modem links where you don't want to send out redundant ACKs.
-ben
--
"Time is of no importance, Mr. President, only life is important."
Don't Email: <dont@kvack.org>.
next prev parent reply other threads:[~2006-03-20 16:06 UTC|newest]
Thread overview: 65+ 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 22:40 ` David S. Miller
2006-03-06 22:50 ` Stephen Hemminger
2006-03-06 22:50 ` Stephen Hemminger
2006-03-07 3:13 ` Shirley Ma
2006-03-07 21:44 ` [openib-general] " Matt Leininger
2006-03-07 21:44 ` Matt Leininger
2006-03-07 21:49 ` [openib-general] " Stephen Hemminger
2006-03-07 21:49 ` Stephen Hemminger
2006-03-07 21:53 ` [openib-general] " Michael S. Tsirkin
2006-03-07 21:53 ` Michael S. Tsirkin
2006-03-08 0:11 ` [openib-general] " Matt Leininger
2006-03-08 0:11 ` Matt Leininger
2006-03-08 0:18 ` [openib-general] " David S. Miller
2006-03-08 0:18 ` David S. Miller
2006-03-08 1:17 ` [openib-general] " Roland Dreier
2006-03-08 1:17 ` Roland Dreier
2006-03-08 1:23 ` [openib-general] " David S. Miller
2006-03-08 1:23 ` David S. Miller
2006-03-08 1:34 ` [openib-general] " Roland Dreier
2006-03-08 1:34 ` Roland Dreier
2006-03-08 12:53 ` Michael S. Tsirkin
2006-03-08 12:53 ` Michael S. Tsirkin
2006-03-08 20:53 ` David S. Miller
2006-03-09 23:48 ` David S. Miller
2006-03-09 23:48 ` David S. Miller
2006-03-10 0:10 ` Michael S. Tsirkin
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 7:18 ` David S. Miller
2006-03-10 0:21 ` Rick Jones
2006-03-10 0:21 ` Rick Jones
2006-03-10 7:23 ` David S. Miller
2006-03-10 7:23 ` David S. Miller
2006-03-10 17:44 ` Rick Jones
2006-03-10 17:44 ` Rick Jones
2006-03-20 9:06 ` Michael S. Tsirkin
2006-03-20 9:06 ` Michael S. Tsirkin
2006-03-20 9:55 ` David S. Miller
2006-03-20 9:55 ` David S. Miller
2006-03-20 10:22 ` Michael S. Tsirkin
2006-03-20 10:22 ` Michael S. Tsirkin
2006-03-20 10:37 ` David S. Miller
2006-03-20 10:37 ` David S. Miller
2006-03-20 11:27 ` Michael S. Tsirkin
2006-03-20 11:27 ` Michael S. Tsirkin
2006-03-20 11:47 ` Arjan van de Ven
2006-03-20 11:47 ` Arjan van de Ven
2006-03-20 11:49 ` Lennert Buytenhek
2006-03-20 11:49 ` Lennert Buytenhek
2006-03-20 11:53 ` Arjan van de Ven
2006-03-20 11:53 ` Arjan van de Ven
2006-03-20 13:35 ` Michael S. Tsirkin
2006-03-20 13:35 ` Michael S. Tsirkin
2006-03-20 12:04 ` Michael S. Tsirkin
2006-03-20 12:04 ` Michael S. Tsirkin
2006-03-20 15:09 ` Benjamin LaHaise [this message]
2006-03-20 15:09 ` Benjamin LaHaise
2006-03-20 18:58 ` Rick Jones
2006-03-20 18:58 ` Rick Jones
2006-03-20 23:00 ` David S. Miller
2006-03-20 23:00 ` David S. Miller
2006-04-27 4:13 ` Troy Benjegerdes
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