From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Aizman Subject: Re: [ANNOUNCE 0/6] Open-iSCSI High-Performance Initiator for Linux Date: Tue, 08 Mar 2005 22:25:29 -0800 Message-ID: <422E96D9.6090202@yahoo.com> References: <422BFCB2.6080309@yahoo.com> <20050309050434.GT3163@waste.org> <422E8EEB.7090209@yahoo.com> <20050309060544.GW3120@waste.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Received: from smtp108.mail.sc5.yahoo.com ([66.163.170.6]:63064 "HELO smtp108.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S262170AbVCIGZ7 (ORCPT ); Wed, 9 Mar 2005 01:25:59 -0500 In-Reply-To: <20050309060544.GW3120@waste.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Matt Mackall Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Matt Mackall wrote: >On Tue, Mar 08, 2005 at 09:51:39PM -0800, Alex Aizman wrote: > > >>Matt Mackall wrote: >> >> >> >>>How big is the userspace client? >>> >>> >>> >>Hmm.. x86 executable? source? >> >>Anyway, there's about 12,000 lines of user space code, and growing. In >>the kernel we have approx. 3,300 lines. >> >> >> >>>>- 450MB/sec Read on a single connection (2-way 2.4Ghz Opteron, 64KB block >>>>size); >>>> >>>> >>>With what network hardware and drives, please? >>> >>> >>> >>Neterion's 10GbE adapters. RAM disk on the target side. >> >> > >Ahh. > >Snipped my question about userspace deadlocks - that was the important >one. It is in fact why the sfnet one is written as it is - it >originally had a userspace component and turned out to be easy to >deadlock under load because of it. > > > There's (or at least was up until today) an ongoing discussion on our mailing list at http://groups-beta.google.com/group/open-iscsi. The short and long of it: the problem can be solved, and it will. Couple simple things we already do: mlockall() to keep the daemon un-swapped, and also looking into potential dependency created by syslog (there's one for 2.4 kernel, not sure if this is an issue for 2.6). The sfnet is a learning experience; it is by no means a proof that it cannot be done. Alex