From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [ofa-general] Re: [PATCH 2/3][NET_BATCH] net core use batching Date: Tue, 9 Oct 2007 13:53:40 -0700 Message-ID: <20071009135340.33e5922c@freepuppy.rosehill> References: <470AD5D7.1070000@garzik.org> <20071008.184126.124062865.davem@davemloft.net> <20071009.134331.35664207.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: johnpol@2ka.mipt.ru, Robert.Olsson@data.slu.se, herbert@gondor.apana.org.au, gaagaan@gmail.com, jeff@garzik.org, rdreier@cisco.com, peter.p.waskiewicz.jr@intel.com, hadi@cyberus.ca, mcarlson@broadcom.com, andi@firstfloor.org, general@lists.openfabrics.org, netdev@vger.kernel.org, tgraf@suug.ch, randy.dunlap@oracle.com, jagana@us.ibm.com, kaber@trash.net, mchan@broadcom.com, sri@us.ibm.com To: David Miller Return-path: In-Reply-To: <20071009.134331.35664207.davem@davemloft.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: general-bounces@lists.openfabrics.org Errors-To: general-bounces@lists.openfabrics.org List-Id: netdev.vger.kernel.org On Tue, 09 Oct 2007 13:43:31 -0700 (PDT) David Miller wrote: > From: Andi Kleen > Date: 09 Oct 2007 18:51:51 +0200 > > > Hopefully that new qdisc will just use the TX rings of the hardware > > directly. They are typically large enough these days. That might avoid > > some locking in this critical path. > > Indeed, I also realized last night that for the default qdiscs > we do a lot of stupid useless work. If the queue is a FIFO > and the device can take packets, we should send it directly > and not stick it into the qdisc at all. > > > If the data is just passed on to the hardware queue, why is any > > locking needed at all? (except for the driver locking of course) > > Absolutely. > > Our packet scheduler subsystem is great, but by default it should just > get out of the way. I was thinking why not have a default transmit queue len of 0 like the virtual devices. -- Stephen Hemminger