From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752467Ab3CAVYF (ORCPT ); Fri, 1 Mar 2013 16:24:05 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:33374 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751988Ab3CAVYD (ORCPT ); Fri, 1 Mar 2013 16:24:03 -0500 Date: Fri, 01 Mar 2013 16:24:00 -0500 (EST) Message-Id: <20130301.162400.1645765127882618751.davem@davemloft.net> To: eliezer.tamir@linux.jf.intel.com Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, jesse.brandeburg@intel.com, e1000-devel@lists.sourceforge.net, willemb@google.com, andi@firstfloor.org, hpa@zytor.com, eliezer@tamir.org.il Subject: Re: [RFC PATCH 0/5] net: low latency Ethernet device polling From: David Miller In-Reply-To: <20130227175549.10611.82188.stgit@gitlad.jf.intel.com> References: <20130227175549.10611.82188.stgit@gitlad.jf.intel.com> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (shards.monkeyblade.net [0.0.0.0]); Fri, 01 Mar 2013 13:24:06 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eliezer Tamir Date: Wed, 27 Feb 2013 09:55:49 -0800 > This patchset adds the ability for the socket layer code to poll directly > on an Ethernet device's RX queue. This eliminates the cost of the interrupt > and context switch and with proper tuning allows us to get very close > to the HW latency. > > This is a follow up to Jesse Brandeburg's Kernel Plumbers talk from last year > http://www.linuxplumbersconf.org/2012/wp-content/uploads/2012/09/2012-lpc-Low-Latency-Sockets-slides-brandeburg.pdf I just wanted to say that I like this work a lot. It proves a lot of things I try to impress upon people who talk about how RDMA is such a "must have" because the software stack can't possibly give anything near HW latency. Obviously such arguments are complete bullshit as is shown by these changes. This is exactly the kind of approach that makes sense rather than trying to put entire TCP stacks in the network card firmware. Thanks again for doing this work and I look forward to applying this stuff once all the kinks are worked out. The folks in the Intel NIC group continue to impress me.