From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [RFC] New driver API to speed up small packets xmits Date: Thu, 10 May 2007 14:32:47 -0400 Message-ID: <4643654F.5060207@hp.com> References: <46435412.50800@hp.com> <464360D6.4080402@hp.com> <46436274.4060804@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Krishna Kumar2 , Evgeniy Polyakov , netdev@vger.kernel.org To: Rick Jones Return-path: Received: from atlrel6.hp.com ([156.153.255.205]:36792 "EHLO atlrel6.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753569AbXEJSct (ORCPT ); Thu, 10 May 2007 14:32:49 -0400 In-Reply-To: <46436274.4060804@hp.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Rick Jones wrote: > Vlad Yasevich wrote: >> Rick Jones wrote: >> >>>> It is the reverse - GSO will segment one super-packet just before >>>> calling >>>> the driver so that the stack is traversed only once. In my case, I am >>>> trying to send out multiple skbs, possibly small packets, in one shot. >>>> GSO will not help for small packets. >>> >>> If there are small packets that implies small sends, which suggests that >>> they would be coalesced either implicitly by the Nagle algorithm or >>> explicitly with TCP_CORK no? >>> >>> rick jones >>> - >> >> >> May be for TCP? What about other protocols? > > There are other protocols?-) True, UDP, and I suppose certain modes of > SCTP might be sending streams of small packets, as might TCP with > TCP_NODELAY set. > > Do they often queue-up outside the driver? Not sure if DCCP might fall into this category as well... I think the idea of this patch is gather some number of these small packets and shove them at the driver in one go instead of each small packet at a time. I might be helpful, but reserve judgment till I see more numbers. -vlad