From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin Subject: Re: Performance of SCST versus STGT Date: Thu, 17 Jan 2008 12:48:28 +0300 Message-ID: <478F246C.4040400@vlnb.net> References: <20080117184052F.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-relay-01.mailcluster.net ([77.221.130.213]:33731 "EHLO mail-relay-01.mailcluster.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbYAQJs3 (ORCPT ); Thu, 17 Jan 2008 04:48:29 -0500 In-Reply-To: <20080117184052F.fujita.tomonori@lab.ntt.co.jp> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: FUJITA Tomonori Cc: bart.vanassche@gmail.com, stgt-devel@lists.berlios.de, linux-scsi@vger.kernel.org, scst-devel@lists.sourceforge.net, James.Bottomley@hansenpartnership.com, erezz@voltaire.com FUJITA Tomonori wrote: > On Thu, 17 Jan 2008 10:27:08 +0100 > "Bart Van Assche" wrote: > > >>Hello, >> >>I have performed a test to compare the performance of SCST and STGT. >>Apparently the SCST target implementation performed far better than >>the STGT target implementation. This makes me wonder whether this is >>due to the design of SCST or whether STGT's performance can be >>improved to the level of SCST ? >> >>Test performed: read 2 GB of data in blocks of 1 MB from a target (hot >>cache -- no disk reads were performed, all reads were from the cache). >>Test command: time dd if=/dev/sde of=/dev/null bs=1M count=2000 >> >> STGT read SCST read >> performance (MB/s) performance (MB/s) >>Ethernet (1 Gb/s network) 77 89 >>IPoIB (8 Gb/s network) 82 229 >>SRP (8 Gb/s network) N/A 600 >>iSER (8 Gb/s network) 80 N/A >> >>These results show that SCST uses the InfiniBand network very well >>(effectivity of about 88% via SRP), but that the current STGT version >>is unable to transfer data faster than 82 MB/s. Does this mean that >>there is a severe bottleneck present in the current STGT >>implementation ? > > > I don't know about the details but Pete said that he can achieve more > than 900MB/s read performance with tgt iSER target using ramdisk. > > http://www.mail-archive.com/stgt-devel@lists.berlios.de/msg00004.html Please don't confuse multithreaded latency insensitive workload with single threaded, hence latency sensitive one. > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >