From owner-freebsd-hardware@FreeBSD.ORG Fri Mar 12 02:32:33 2004 Return-Path: Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BF20016A4CE for ; Fri, 12 Mar 2004 02:32:33 -0800 (PST) Received: from osiris.ipform.ru (osiris.itlegion.ru [212.248.52.90]) by mx1.FreeBSD.org (Postfix) with ESMTP id D1C7443D1F for ; Fri, 12 Mar 2004 02:32:32 -0800 (PST) (envelope-from matrix@itlegion.ru) Received: from artem (artem.office.ipform.ru [192.168.0.12]) by osiris.ipform.ru (8.12.6/8.12.6) with ESMTP id i2CAWUJ3083415 for ; Fri, 12 Mar 2004 13:32:31 +0300 (MSK) (envelope-from matrix@itlegion.ru) X-AntiVirus: Checked by Dr.Web (http://www.drweb.net) Message-ID: <002f01c4081c$bd720810$0c00a8c0@artem> From: "Artem Koutchine" To: References: Date: Fri, 12 Mar 2004 13:28:18 +0300 Organization: IT Legion MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: Multiprocessor system VS one processor system X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Mar 2004 10:32:33 -0000 Hi! I need to understand something very clear. As I understand FreeBSD (as of 4.9) runs one process per one CPU. This means, that if i have dual systems with 500Mhz CPUs one process can never run faster than on a single 500Mhz CPU. However, if i substitute those two CPUs with one 1000Mhz, that one process will run twice as fast than on dual 500Mhz, however, to box will become a bit less responsive, because in a dual box when one CPU is loaded, another one may have some spare time to respond. However, in case of very loaded box both CPUs a extremely loaded and the box will be as responsive as single 1000Mhz CPU box 100% loaded. So, according to what i just said there is not real reason to setup a dual CPU box under FREEBSD unless you want to have 5000Mhz box, but there is no CPU with such speed, so you put two 2500Mhz CPU in it and if you are running a lot of processes with short run periods you will get overal perfomance somewhere near 5000Mhz. However, when i subsituted two 500Mhz CPUs with 1500Mhz one (even with less 2nd level cache) on a heavy loaded web server i notice that sites started to load faster. So, it seems as one 3X Mhz CPU is faster that two X MHz CPUs, at least for web server with sql base and many perl scripts. So, there are two questions: 1) Am I right or am wrong? 2) Does FreeBSD 5.X run one process only on one CPU or it can run on thread of a process on one CPU and another thread on another CPU? Regards, Artem