Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936Ab0HWSDa (ORCPT ); Mon, 23 Aug 2010 14:03:30 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:49638 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751423Ab0HWSD1 convert rfc822-to-8bit (ORCPT ); Mon, 23 Aug 2010 14:03:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=ZQYC3IW+Az+3/oObzLwW2i4wXF0RQ6nJeXlCiu2EQUnbToM4odDUhkSS/XU5Dn94VG IbdkJLWwvgFvLHrEqB9NuICLhDiKVvCh4IoGMA2f+IW78tztFJxnvwH0EEX+S+OMBpki logUq8iXaUmZ5fhSfFUjsbNBU49zGKzsn58oE= MIME-Version: 1.0 In-Reply-To: References: <594039.74663.qm@web111905.mail.gq1.yahoo.com> <1282144271.3035.31.camel@mulgrave.site> <1282148296.3035.49.camel@mulgrave.site> <4C6C1D70.7020502@vlnb.net> <41A1E2691BBB412BADCDE5F515CD8EDA@usish.com.cn> <8A96806D-6CD7-44AD-8A9D-143C098C95A4@uni-paderborn.de> <1282256949.30453.278.camel@haakon2.linux-iscsi.org> <4C701E08.2020005@vlnb.net> <1282423398.3015.39.camel@mulgrave.site> <1282508953.3042.102.camel@mulgrave.site> <4C727BEB.9020100@scalableinformatics.com> Date: Mon, 23 Aug 2010 14:03:26 -0400 Message-ID: Subject: Re: [Scst-devel] Fwd: Re: linuxcon 2010... From: Chetan Loke To: Bart Van Assche Cc: landman@scalableinformatics.com, James Bottomley , Vladislav Bolkhovitin , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, scst-devel Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1912 Lines: 43 I actually received 3+ off-post emails asking whether I was talking about initiator or target in the 100K IOPS case below and what did I mean by the ACKs. I was referring to the 'Initiator' side. ACKs == When scsi-ML down-calls the LLD via the queue-command, process the sgl's(if you like) and then trigger the scsi_done up-call path. Chetan Loke On Mon, Aug 23, 2010 at 12:07 PM, Chetan Loke wrote: > On Mon, Aug 23, 2010 at 11:11 AM, Bart Van Assche wrote: > >> >> There is an important design difference between SCST and LIO: SCST by >> defaults creates multiple threads to process the I/O operations for a >> storage target, while LIO only creates a single thread per storage target. >> This makes SCST perform measurably faster. >> > > Forget that. You could have discussed this if there were code reviews > or other mainline inclusion emails from James B. From what I have > heard, the decision was taken around 8-9 months back. > Would anyone like to either comment/validate/refute this please?  If > not then I would kindly request these guys to stop taking us for a > test drive. And also I'm not sure when was the last time James B. > bench-marked our scsi-stack. Even if I ACK in the xmit-path then I > can't push more than 100K IOPs. But other folks have re-engineered our > linux-scsi stack and from what I've heard they can push > 300K+ IOPs. > So I would just ignore performance discussion because I don't think > folks have done even simple lame experiments in the last 1 year. Or > may be I'm completely wrong and so please enlighten me so that I can > re-run the tests. > > >> Bart. >> > Chetan Loke > -- 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/