From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Fink Subject: Re: [ofa-general] Re: [PATCH 2/3][NET_BATCH] net core use batching Date: Wed, 10 Oct 2007 12:02:15 -0400 Message-ID: <20071010120215.7ec19323.billfink@mindspring.com> References: <20071009135340.33e5922c@freepuppy.rosehill> <20071009.142235.74385364.davem@davemloft.net> <1191967006.5324.14.camel@localhost> <20071009.170435.43504422.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: hadi@cyberus.ca, shemminger@linux-foundation.org, andi@firstfloor.org, jeff@garzik.org, johnpol@2ka.mipt.ru, herbert@gondor.apana.org.au, gaagaan@gmail.com, Robert.Olsson@data.slu.se, netdev@vger.kernel.org, rdreier@cisco.com, peter.p.waskiewicz.jr@intel.com, mcarlson@broadcom.com, jagana@us.ibm.com, general@lists.openfabrics.org, mchan@broadcom.com, tgraf@suug.ch, randy.dunlap@oracle.com, sri@us.ibm.com, kaber@trash.net To: David Miller Return-path: Received: from elasmtp-kukur.atl.sa.earthlink.net ([209.86.89.65]:45353 "EHLO elasmtp-kukur.atl.sa.earthlink.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756015AbXJJQD4 (ORCPT ); Wed, 10 Oct 2007 12:03:56 -0400 In-Reply-To: <20071009.170435.43504422.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, 09 Oct 2007, David Miller wrote: > From: jamal > Date: Tue, 09 Oct 2007 17:56:46 -0400 > > > if the h/ware queues are full because of link pressure etc, you drop. We > > drop today when the s/ware queues are full. The driver txmit lock takes > > place of the qdisc queue lock etc. I am assuming there is still need for > > that locking. The filter/classification scheme still works as is and > > select classes which map to rings. tc still works as is etc. > > I understand your suggestion. > > We have to keep in mind, however, that the sw queue right now is 1000 > packets. I heavily discourage any driver author to try and use any > single TX queue of that size. Which means that just dropping on back > pressure might not work so well. > > Or it might be perfect and signal TCP to backoff, who knows! :-) I can't remember the details anymore, but for 10-GigE, I have encountered cases where I was able to significantly increase TCP performance by increasing the txqueuelen to 10000, which is the setting I now use for any 10-GigE testing. -Bill