From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [RFC] [PATCH] Avoid enqueuing skb for default qdiscs Date: Mon, 03 Aug 2009 20:55:25 -0700 (PDT) Message-ID: <20090803.205525.156945388.davem@davemloft.net> References: <20090803.202935.221338243.davem@davemloft.net> <20090804034910.GA30871@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: krkumar2@in.ibm.com, jarkao2@gmail.com, kaber@trash.net, netdev@vger.kernel.org To: herbert@gondor.apana.org.au Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:60987 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755098AbZHDDzR (ORCPT ); Mon, 3 Aug 2009 23:55:17 -0400 In-Reply-To: <20090804034910.GA30871@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: From: Herbert Xu Date: Tue, 4 Aug 2009 11:49:10 +0800 > On Mon, Aug 03, 2009 at 08:29:35PM -0700, David Miller wrote: >> >> Although PFIFO is not work-conserving, isn't it important to retain >> ordering? What if higher priority packets are in the queue when we >> enqueue? This new bypass will send the wrong packet, won't it? > > The bypass only kicks in if the queue length is zero. Thanks for explaining, makes sense now. >> I'm beginning to think, if we want to make the default case go as fast >> as possible, we should just bypass everything altogether. The entire >> qdisc layer, all of it. > > Can you be more specific? AFAICS he's already bypassing the qdisc > layer when it can be done safely. Ignore this, it's based upon my missing the part where this bypass only triggers when the qdisc is empty.