From owner-freebsd-hackers@FreeBSD.ORG Wed Sep 13 17:00:23 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6632E16A40F for ; Wed, 13 Sep 2006 17:00:23 +0000 (UTC) (envelope-from mwm-keyword-freebsdhackers2.e313df@mired.org) Received: from mired.org (vpn.mired.org [66.92.153.74]) by mx1.FreeBSD.org (Postfix) with SMTP id ABCC443D45 for ; Wed, 13 Sep 2006 17:00:22 +0000 (GMT) (envelope-from mwm-keyword-freebsdhackers2.e313df@mired.org) Received: (qmail 50006 invoked by uid 1001); 13 Sep 2006 17:00:26 -0000 Received: by bhuda.mired.org (tmda-sendmail, from uid 1001); Wed, 13 Sep 2006 13:00:26 -0400 (EDT) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17672.14633.859999.417883@bhuda.mired.org> Date: Wed, 13 Sep 2006 13:00:25 -0400 To: Danny Braniss In-Reply-To: References: X-Mailer: VM 7.17 under 21.4 (patch 19) "Constant Variable" XEmacs Lucid X-Primary-Address: mwm@mired.org X-face: "5Mnwy%?j>IIV\)A=):rjWL~NB2aH[}Yq8Z=u~vJ`"(,&SiLvbbz2W`; h9L,Yg`+vb1>RG% *h+%X^n0EZd>TM8_IB;a8F?(Fb"lw'IgCoyM.[Lg#r\ X-Delivery-Agent: TMDA/1.0.3 (Seattle Slew) From: Mike Meyer Cc: freebsd-hackers@freebsd.org Subject: Re: numbers don't lie ... X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Sep 2006 17:00:23 -0000 In , Danny Braniss typed: > Im testing these 2 boxes, Sun X4100 and Dell-2950, and: > > SUN X4100: Dual Core AMD Opteron(tm) Processor 280 (2393.19-MHz K8-class CPU) > one 70g sata disk > DELL 2950: Intel(R) Xeon(TM) CPU 3.20GHz (3192.98-MHz K8-class CPU) > 4 sata disks + raid0 > > they both run identical 6.1-STABLE. > > my 'cpu benchmark' shows the amd being much better than the intel. > but, doing a make buildworld give interesting results: > > dell-2950 : make -j16 TARGET_ARCH=amd64 buildworld : 24m17.41s real 1h3m3.26s > user 17m15.07s sys > dell-2950 : make -j8 TARGET_ARCH=amd64 buildworld : 24m8.28s real 1h2m59.38s > user 16m16.20s sys > > sunfire : make -j16 TARGET_ARCH=amd64 buildworld : 24m21.38s real 49m6.68s > user 14m22.64s sys > sunfire : make -j8 TARGET_ARCH=amd64 buildworld : 23m47.69s real 48m53.58s > user 13m44.81s sys > > which probably says something about my 'cpu benchmark' :-( Yes - that it's not very good at predicting performance on a parallel make. That's not surprising, as it's true of most benchmarks. You might want to check out some of the benchmarks in the ports tree as well. > but why is the user time so much different between the boxes? What's the CPU configuration? The AMD is dual core - is that it? Could the Xeon be dual-core and hyperthreaded, so it's got that many more CPUs to contribute towards user time? To illustrate, I have numbers for "make -j4" for a P4 with and without hyperthreading enabled: machdep.hyperthreading_allowed: 1 -> 0 50m55.99s real 35m28s.19 user 8m20s.02 sys machdep.hyperthreading_allowed: 0 -> 1 38m48s.85 real 55m2s.43 user 12m27s.90 sys Note the effect of the second CPU on the user time. http://www.mired.org/consulting.html Independent Network/Unix/Perforce consultant, email for more information.