From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Bart Van Assche" Subject: Re: Integration of SCST in the mainstream Linux kernel Date: Wed, 6 Feb 2008 13:16:43 +0100 Message-ID: References: <1201639331.3069.58.camel@localhost.localdomain> <20080130083239E.fujita.tomonori@lab.ntt.co.jp> <47A89660.1080804@Voltaire.COM> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from wr-out-0506.google.com ([64.233.184.228]:42284 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762225AbYBFMQt (ORCPT ); Wed, 6 Feb 2008 07:16:49 -0500 Received: by wr-out-0506.google.com with SMTP id c48so2597816wra.23 for ; Wed, 06 Feb 2008 04:16:45 -0800 (PST) In-Reply-To: <47A89660.1080804@Voltaire.COM> Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Erez Zilber Cc: FUJITA Tomonori , rdreier@cisco.com, James.Bottomley@hansenpartnership.com, torvalds@linux-foundation.org, akpm@linux-foundation.org, vst@vlnb.net, linux-scsi@vger.kernel.org, scst-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org On Feb 5, 2008 6:01 PM, Erez Zilber wrote: > > Using such large values for FirstBurstLength will give you poor > performance numbers for WRITE commands (with iSER). FirstBurstLength > means how much data should you send as unsolicited data (i.e. without > RDMA). It means that your WRITE commands were sent without RDMA. Sorry, but I'm afraid you got this wrong. When the iSER transport is used instead of TCP, all data is sent via RDMA, including unsolicited data. If you have look at the iSER implementation in the Linux kernel (source files under drivers/infiniband/ulp/iser), you will see that all data is transferred via RDMA and not via TCP/IP. Bart Van Assche.