From owner-freebsd-performance@FreeBSD.ORG Sun Sep 19 05:25:12 2010 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A8A57106566C for ; Sun, 19 Sep 2010 05:25:12 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id 32F648FC08 for ; Sun, 19 Sep 2010 05:25:11 +0000 (UTC) Received: by bwz15 with SMTP id 15so4713321bwz.13 for ; Sat, 18 Sep 2010 22:25:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:message-id:date:from :user-agent:mime-version:to:subject:references:in-reply-to :x-enigmail-version:content-type:content-transfer-encoding; bh=xMybVCibL2snLqotz8+kk6pDRK5QTkIlB2WQromUjXc=; b=JlfSnBTju+5TilrPuVTK2nypLkdpC6BowZ8nl/SRnBUQqCjhUT3UbNQiD3q/4n70wp hlWf32ZZyfeuTTExlg3UBIg2Kwlb5DuUBdAyNGqUbZMpx43Pebw8M13wB2XAORDIlh3F wDpAK7ZwGGclrb4Ne5yvCjyRw6cumGGHOhlNA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=MO31YJVWVrxUKo9Ocu4uBLArHKHjdm6KsJD7A00zbC5QjQOMa4hUGA8HD2xRJzPciB X6Sn3W4X7pZhFLofM0LmQWW3hc1T/6LqKrjfK1TfEaGNqKS7erKWjVDuIT7khkskHF/g zcnm4V0ewxPSRUx1iIGi5iqErxTRlFtT4tmuw= Received: by 10.204.6.75 with SMTP id 11mr5455506bky.95.1284872244791; Sat, 18 Sep 2010 21:57:24 -0700 (PDT) Received: from mavbook.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id f18sm5250825bkf.3.2010.09.18.21.57.22 (version=SSLv3 cipher=RC4-MD5); Sat, 18 Sep 2010 21:57:23 -0700 (PDT) Sender: Alexander Motin Message-ID: <4C959830.3060808@FreeBSD.org> Date: Sun, 19 Sep 2010 07:57:20 +0300 From: Alexander Motin User-Agent: Thunderbird 2.0.0.24 (X11/20100402) MIME-Version: 1.0 To: freebsd-performance@freebsd.org References: <4C4AF046.40507@FreeBSD.org> In-Reply-To: <4C4AF046.40507@FreeBSD.org> X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Sun, 19 Sep 2010 10:42:14 +0000 Subject: Re: Intel TurboBoost in practice X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 19 Sep 2010 05:25:12 -0000 Getting back to that topic I would like to share some more results. This time I was testing Core(TM) i7 870 @ 2.93GHz. It has 8 logical cores and bigger allowed TurboBoost effect. I was testing real time of net/mpd5 port building, using single CPU. I was testing it with HZ=1000 with different C-states allowed and with/without kern.eventtimer.idletick sysctl enabled (supported by the latest event timer code in HEAD). This sysctl, when disabled, allows to avoid most of timer interrupts on idle cores, allowing them to sleep deeper. Here is results: x C1i + C2i * C3i % C1 # C2 @ C3 +-----------------------------------------------------------------+ | @ | | # O ** + % xx | |##@O@ + ** + %%% xx | |##@O@ + ** +++ %%% xx x| | |_A_| | | |___A__M_| | | A| | | |A | ||A_| | | |A| | +-----------------------------------------------------------------+ N Min Max Median Avg Stddev x 8 12.01 12.14 12.02 12.03125 0.04421942 + 8 11.45 11.68 11.67 11.61125 0.097897541 Difference at 95.0% confidence -0.42 +/- 0.0814651 -3.49091% +/- 0.677113% (Student's t, pooled s = 0.0759582) * 8 11.51 11.54 11.52 11.52375 0.011877349 Difference at 95.0% confidence -0.5075 +/- 0.0347234 -4.21818% +/- 0.28861% (Student's t, pooled s = 0.0323761) % 8 11.9 11.93 11.92 11.915 0.011952286 Difference at 95.0% confidence -0.11625 +/- 0.0347382 -0.966234% +/- 0.288733% (Student's t, pooled s = 0.0323899) # 8 10.72 10.79 10.73 10.74875 0.031819805 Difference at 95.0% confidence -1.2825 +/- 0.0413146 -10.6597% +/- 0.343394% (Student's t, pooled s = 0.0385218) @ 8 10.76 10.8 10.79 10.785 0.014142136 Difference at 95.0% confidence -1.24625 +/- 0.035208 -10.3584% +/- 0.292638% (Student's t, pooled s = 0.032828) As you may see, with full timer interrupt rate TurboBoost effect (part of it, that enabled by some number of idle cores) is about 3-4%. CPUs are not sleeping long enough. But without extra interrupts on idle cores effect increasing to more then 10%! -- Alexander Motin