From owner-freebsd-questions@FreeBSD.ORG Mon Feb 25 10:00:18 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7C05216A406 for ; Mon, 25 Feb 2008 10:00:18 +0000 (UTC) (envelope-from tigger@lvlworld.com) Received: from lilypie.com (lilypie.com [67.19.138.162]) by mx1.freebsd.org (Postfix) with ESMTP id 4789713C467 for ; Mon, 25 Feb 2008 10:00:17 +0000 (UTC) (envelope-from tigger@lvlworld.com) Received: (qmail 58094 invoked from network); 25 Feb 2008 10:00:14 -0000 Received: from unknown (HELO piglet) (202.183.125.35) by lilypie.com with ESMTP; 25 Feb 2008 10:00:14 -0000 Date: Mon, 25 Feb 2008 21:01:34 +1100 From: Tigger To: freebsd-questions@freebsd.org Message-ID: <20080225210134.2d0e2908@piglet> In-Reply-To: <47C18665.9050600@FreeBSD.org> References: <20080224110010.GA4447@edward.lilypie.com> <47C1590F.3020605@bsdforen.de> <20080224230744.50539c03@piglet> <47C18665.9050600@FreeBSD.org> X-Mailer: Claws Mail 3.3.0 (GTK+ 2.12.1; i386-portbld-freebsd7.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: Dual core CPU's, but only 2 CPU's in-use? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Feb 2008 10:00:18 -0000 On Sun, 24 Feb 2008 15:59:49 +0100 Kris Kennaway wrote: > Tigger wrote: > > On Sun, 24 Feb 2008 12:46:23 +0100 > > Dominic Fandrey wrote: > > > >> Tigger wrote: > >>> Hello. I have a Xeon system with 2 CPU's installed (dual-cores). > >>> Under FreeBSD 6.2, a systat reported 4 CPUs in use and so did > >>> dmesg. > >>> > >>> Under FreeBSD 6.3, dmesg is reporting the 4 CPUs, but systat is > >>> only reporting 2 CPUs (CPU 0 and CPU 2). > >>> > >>> How do I enabled the second cores on the CPU's or are they really > >>> running but systat is not reporting the CPU load across the cores? > >> You can run 'top -S' to check how many idle processes exist. If > >> there are four, everything is fine. > >> > > > > > > Sadly, no luck. Only cpu0 and cpu2 are reported: > > > > PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU > > COMMAND 11 root 1 171 52 0K 8K CPU2 2 143:43 > > 92.38% idle: cpu2 13 root 1 171 52 0K 8K RUN 0 > > 142:33 92.04% idle: cpu0 > > Are your CPUs really dual-core, or single core + hyperthreaded? > > Kris > Thank you! Your email sent me off to do what I should have done first - some research. I assumed (wrongly) that 'Logical CPUs per core: 2' meant 'Dual Core', and when I saw the following: FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs cpu0 (BSP): APIC ID: 0 cpu1 (AP): APIC ID: 1 cpu2 (AP): APIC ID: 6 cpu3 (AP): APIC ID: 7 I also thought 'Dual Core', however this is not the case. The CPU's are single core with Hyper Threading Tech. But this research has also lead to some confusion. Its clear there are 2 CPU with 2 Logical cores each, but only 2 cores are in use - why? Also, the 'man (4) smp' talks about (possible) performance issues with Hyper Threading enabled - does this mean I should set 'machdep.hlt_logical_cpus 1' (it is currently set to 0) - or because the Logical Cores are not being used I can forget about this? -Tig