From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin Subject: Re: Performance of SCST versus STGT Date: Tue, 22 Jan 2008 14:33:13 +0300 Message-ID: <4795D479.1080805@vlnb.net> References: <20080117174542.GC29650@osc.edu> <479096D2.8090003@vlnb.net> <20080122122657R.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080122122657R.fujita.tomonori-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: stgt-devel-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: stgt-devel-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org To: FUJITA Tomonori Cc: James.Bottomley-JuX6DAaQMKPCXq6kfMZ53/egYHeGw8Jk@public.gmane.org, stgt-devel-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, scst-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-scsi@vger.kernel.org FUJITA Tomonori wrote: > The big problem of stgt iSER is disk I/Os (move data between disk and > page cache). We need a proper asynchronous I/O mechanism, however, > Linux doesn't provide such and we use a workaround, which incurs large > latency. I guess, we cannot solve this until syslets is merged into > mainline. Hmm, SCST also doesn't have ability to use asynchronous I/O, but that doesn't prevent it from showing good performance. Vlad