From owner-freebsd-stable@FreeBSD.ORG Thu Nov 29 22:22:20 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 E846316A421 for ; Thu, 29 Nov 2007 22:22:20 +0000 (UTC) (envelope-from mattjreimer@gmail.com) Received: from py-out-1112.google.com (py-out-1112.google.com [64.233.166.183]) by mx1.freebsd.org (Postfix) with ESMTP id 92FC613C45D for ; Thu, 29 Nov 2007 22:22:20 +0000 (UTC) (envelope-from mattjreimer@gmail.com) Received: by py-out-1112.google.com with SMTP id u77so4486333pyb for ; Thu, 29 Nov 2007 14:22:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=L1YfkbN7O8tKIi5Sd82FlNfSPFLCGYfNdE0UaPkUDes=; b=tx+KLIv7jO/skC5e8K7r6kPTE2GNBjiiEBiH/SAa+UDb0QELbybF3m0UJbOTSs5y1WGe4Vpe53SraMp7G5YyZvdg24GdSBNTlZnFUuEETW9OcFiQC1O7BjJGBxX9fZRkDHE3RiCGWKXebi+4JKedyGmYQE4WT9eBBtYzmRG/Yyk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ZkDwIoOwNexV1jTvXT1S5lyXnsJ/gRG/RsZVcRBa6WW57TSDiVG6y8PftcU6EN9ScjtuK9pWDdcvJmhmk8LvQ5TfTkpCqXBdvqnyyGHrpimGbMwb81sbidB+56oi2lMHD3/20ArJ3pcyiy1wiPVIgijAl+/ob1M6JsFtQzghRDs= Received: by 10.35.91.1 with SMTP id t1mr8099241pyl.1196374938332; Thu, 29 Nov 2007 14:22:18 -0800 (PST) Received: by 10.35.58.11 with HTTP; Thu, 29 Nov 2007 14:22:17 -0800 (PST) Message-ID: Date: Thu, 29 Nov 2007 14:22:17 -0800 From: "Matt Reimer" To: "Kris Kennaway" In-Reply-To: <474F1105.5020708@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <474F0BDF.8070605@FreeBSD.org> <474F1105.5020708@FreeBSD.org> Cc: freebsd-stable@freebsd.org, Pete French Subject: Re: Also seeing 2 x quad-core system slower that 2 x dual core 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: Thu, 29 Nov 2007 22:22:21 -0000 On Nov 29, 2007 11:20 AM, Kris Kennaway wrote: > Matt Reimer wrote: > > On Nov 29, 2007 10:58 AM, Kris Kennaway wrote: > >> Pete French wrote: > >>> On the dual core processors this takes about 20 seconds. On the quad > >>> cores it takes about 3 minutes! This is true for both the 32 and 64 bit > >>> versions of FreeBSD :-( > >> That almost certainly has nothing to do with how many CPUs your system > >> has, since rm -rf is a single process running on a single core. > > > > I wonder if I'm seeing this too. Running super-smack on a 2 x quad > > core 1.6GHz Dell 1950 I get about 40000 qps, whereas on a 2 x dual > > core 3.0GHz box I've seen 80000 qps. > > Please, let's try to stay focused :) rm -rf has nothing to do with > super-smack and vice versa. It's relevant to $subject. > > Is this expected? > > It is not very surprising. super-smack is not a good SMP benchmark, it > does stupid things like 1-byte I/O, so it is not very scalable nor a > good model of real-world database activity. Accounting for your CPUs > being twice as fast on the dual core, it roughly says that the benchmark > is not scaling beyond 4 CPUs, which is in line with my own observations. Is sysbench a better benchmark? It gives me 2362.99 on the 2 x dual-core box vs 1327.26 on the 2 x quad-core box. Matt