Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757373AbYBDXA3 (ORCPT ); Mon, 4 Feb 2008 18:00:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754570AbYBDXAR (ORCPT ); Mon, 4 Feb 2008 18:00:17 -0500 Received: from smtp113.sbc.mail.mud.yahoo.com ([68.142.198.212]:31941 "HELO smtp113.sbc.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754748AbYBDXAO (ORCPT ); Mon, 4 Feb 2008 18:00:14 -0500 X-YMail-OSG: WFE4N18VM1knbxyQGDg4wFfr_ENlHuverf2y1ILUXv2LFSZxkmT1onfzdYsh8n4tLZQZMdjGSKN8QkPFeBm__4pcprdxAa7CSi1QFJkxG2Qob6VooZM- X-Yahoo-Newman-Property: ymail-3 Subject: Re: Integration of SCST in the mainstream Linux kernel From: "Nicholas A. Bellinger" To: Alan Cox Cc: Linus Torvalds , James Bottomley , Vladislav Bolkhovitin , Bart Van Assche , Andrew Morton , FUJITA Tomonori , linux-scsi@vger.kernel.org, scst-devel@lists.sourceforge.net, Linux Kernel Mailing List , Mike Christie , Julian Satran In-Reply-To: <20080204224314.113afe7b@core> References: <1201639331.3069.58.camel@localhost.localdomain> <47A05CBD.5050803@vlnb.net> <47A7049A.9000105@vlnb.net> <1202139015.3096.5.camel@localhost.localdomain> <47A73C86.3060604@vlnb.net> <1202144767.3096.38.camel@localhost.localdomain> <47A7488B.4080000@vlnb.net> <1202145901.3096.49.camel@localhost.localdomain> <1202151989.11265.576.camel@haakon2.linux-iscsi.org> <20080204224314.113afe7b@core> Content-Type: text/plain Date: Mon, 04 Feb 2008 14:59:40 -0800 Message-Id: <1202165980.11265.653.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 X-Mailer: Evolution 2.10.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1435 Lines: 36 On Mon, 2008-02-04 at 22:43 +0000, Alan Cox wrote: > > better. So for example, I personally suspect that ATA-over-ethernet is way > > better than some crazy SCSI-over-TCP crap, but I'm biased for simple and > > low-level, and against those crazy SCSI people to begin with. > > Current ATAoE isn't. It can't support NCQ. A variant that did NCQ and IP > would probably trash iSCSI for latency if nothing else. > In the previous iSCSI vs. FCoE points (here is the link again): http://www.ietf.org/mail-archive/web/ips/current/msg02325.html the latency discussion is the one bit that is not mentioned. I always assumed that back then (as with today) the biggest issue was getting ethernet hardware, espically switching equipment down to the sub millisecond latency, and on par with what you would expect from 'real RDMA' hardware. In lowest of the low, say sub 10 ns latency, which is apparently possible with point to point on high-end 10 Gb/sec adapters today, it would be really interesting to know how much more latency would be expected between software iSCSI vs. *oE when we work our way back up the networking stack. Julo, do you have any idea on this..? --nab > > Alan > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/