From owner-freebsd-questions@FreeBSD.ORG Wed Mar 17 12:35:30 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id EC9AD16A4CF for ; Wed, 17 Mar 2004 12:35:30 -0800 (PST) Received: from fed1mtao07.cox.net (fed1mtao07.cox.net [68.6.19.124]) by mx1.FreeBSD.org (Postfix) with ESMTP id 924A243D31 for ; Wed, 17 Mar 2004 12:35:28 -0800 (PST) (envelope-from brently@bjwcs.com) Received: from SAMBA ([68.231.19.60]) by fed1mtao07.cox.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040317203527.RVHD4381.fed1mtao07.cox.net@SAMBA>; Wed, 17 Mar 2004 15:35:27 -0500 From: "Brent Wiese" To: , Date: Wed, 17 Mar 2004 13:35:25 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.5510 In-Reply-To: <20040313133737.GA21068@athena.oekb.co.at> Thread-Index: AcQJAYtOYVdN/KARSHW4uRUGRE4fLADXAyOQ X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Message-Id: <20040317203527.RVHD4381.fed1mtao07.cox.net@SAMBA> Subject: RE: SMP vs. Hyperthreading? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Mar 2004 20:35:31 -0000 > Hi, > > I've got a machine with a P4 that supports HTT (Hyperthreading) so I > thought about setting up a SMP-kernel. SMP <> HT. I'm not an expert on this, but when I went to an Intel conference a couple years ago which discussed hyperthreading, it was made pretty clear it wasn't the same as SMP. But, like I said, I'm not an expert so I don't know what exactly its doing at the very low levels. > Under 5.2.1 it's a different story though: /var/log/messages shows > that there are 2 CPUs but the message indicating the second CPU has > been launched is missing ("/kernel: SMP: AP CPU #1 Launched!"). When I > run a "cpuburn"-Test under 5.2.1 CPU load indicated by "top" shows > 100% so I assume SMP/HTT is not active. That is the message for the second CPU. The first is CPU #0 and is always active. Every dual-cpu machine I've installed SMP kernel on only shows the second CPU launching. > So my primary question is - how do I get SMP running under 5.2.1 with > a hyperthreading-capable P4?? I haven't used 5.x, but in 4.9, there is a specific line in the kernel config for hyperthreading support (to which I've read mixed reviews on this list). Good luck Brent