From owner-freebsd-stable@FreeBSD.ORG Mon Dec 3 11:46:02 2007 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 714E916A421; Mon, 3 Dec 2007 11:46:02 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.freebsd.org (Postfix) with ESMTP id 3CF0B13C4E1; Mon, 3 Dec 2007 11:46:02 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id A90A247046; Mon, 3 Dec 2007 06:50:40 -0500 (EST) Date: Mon, 3 Dec 2007 11:45:53 +0000 (GMT) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Alexey Popov In-Reply-To: <4753C9E4.1060200@chistydom.ru> Message-ID: <20071203114037.G79674@fledge.watson.org> References: <20071201213732.GA16638@cannabis.dataforce.net> <1497741406.20071201230441@rulez.sk> <20071202174540.GA29572@cannabis.dataforce.net> <200712020844.49718.linimon@FreeBSD.org> <4753C9E4.1060200@chistydom.ru> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-stable@freebsd.org, Alexey Vlasov , Mark Linimon Subject: Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Dec 2007 11:46:02 -0000 On Mon, 3 Dec 2007, Alexey Popov wrote: > Mark Linimon wrote: >>> I used 7.0-BETA3 and it is much worse. >> Ouch. A lot of systems see improvement. Thanks for trying it out. I hope >> that one of the people that has been doing the actual work can now comment >> (I am just an onlooker), and that you can be patient in the meantime. >> Unfortunately, Kris, who often looks at these kind of issues, is traveling >> for all of December and thus off the net. > > Is there any other FreeBSD developer who can take care of performance > problems on many-cores systems? Seems like upcoming 7-RELEASE and > 6.3-RELEASE would be completely unusable for us on that kind of systems i.e. > mostly on all modern hardware. There are many FreeBSD developers who care a great deal about the performance of many-core systems. However, it's also very late in the release cycle for 7.0, and this sort of analysis requires a lot of time, so I don't think we will (or should) see any substantial changes at this point as they would require us to significantly extend the release cycle in order to test them properly. The right path forwawrd at this point is to diagnosis the problems and work on fixing them in 8-CURRENT, and assuming they are not highly disruptive, MFC them for FreeBSD 7.1. In general, the most important factor in optimizing performance is to get a good collaboration going between someone who can reproduce the problem, ideally in a way that can be shared with developers so they can also reproduce the problem, and provide testing and feedback over an extended period (several months) while the changes are developed and refined. This is part of the role Kris has been playing with a number of FreeBSD developers -- Jeff, Attilio, myself, etc -- he set up highly reproduceable performance measurements and then worked with us to evaluate various patches to improve performance. That kind of dynamic is invaluable, but it requires users who care a lot about performance (or whatever other factor it is) to spend a fair amount of time helping us. Whether this is by providing a potted benchmark for developers to try out, or if this is by providing access to the test environment on their own systems, it's still critical. I know from previous messages in the thread that you can't provide access to the actual application, but can you provide some sort of potted substitute that has similar performance properties -- be it php page sizes, database query load traces that can be replayed, etc? Robert N M Watson Computer Laboratory University of Cambridge