From owner-freebsd-hackers@FreeBSD.ORG Sat Jul 24 18:45:32 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 00F281065677; Sat, 24 Jul 2010 18:45:32 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-iw0-f182.google.com (mail-iw0-f182.google.com [209.85.214.182]) by mx1.freebsd.org (Postfix) with ESMTP id 9AF998FC1A; Sat, 24 Jul 2010 18:45:31 +0000 (UTC) Received: by iwn35 with SMTP id 35so1746749iwn.13 for ; Sat, 24 Jul 2010 11:45:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=x8WrFernJS3ixnlIu0yCG6CERO/SGfoJmJpVQxg4qc4=; b=vzIYX1R8uy+GFctqG53jC9RJnuIggzjOiGbjG7DQ5rFe6Q82bxTOA0mzqMzUA8AQ4/ StTT6gnRpBnj7IKEW1kOQyiJ5QGS0wc/OVOwS9jgGtnD6m+/kbyWcisKpd3aAuaBByA7 cw+d64vTbxSBX/CpZ5IGQkTtjYAnROYGUy+Vs= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=C8IaIwN94o+BfH5sJCsbeKRXXbgpgafHg+DkhAdVI/WKkAGjJwphAjcDhGgpLnVX4F GkKTdN+F7VZSSNR3cDmGsTvduyqvAIu9UvHab7/Gk44JLWNNRtzZsJiY574TMiWKKTvY KRbn/vTYpOVhDpt5F1BvWOMWusWb8FZtveul0= MIME-Version: 1.0 Received: by 10.231.184.1 with SMTP id ci1mr6027814ibb.39.1279997130674; Sat, 24 Jul 2010 11:45:30 -0700 (PDT) Sender: yanegomi@gmail.com Received: by 10.231.169.18 with HTTP; Sat, 24 Jul 2010 11:45:30 -0700 (PDT) In-Reply-To: References: <4C4AF046.40507@FreeBSD.org> Date: Sat, 24 Jul 2010 11:45:30 -0700 X-Google-Sender-Auth: DYycNkdElj3oewjlwGwek8Qanfw Message-ID: From: Garrett Cooper To: Rui Paulo Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-hackers@freebsd.org, Alexander Motin , freebsd-performance@freebsd.org Subject: Re: Intel TurboBoost in practice 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: Sat, 24 Jul 2010 18:45:32 -0000 On Sat, Jul 24, 2010 at 9:18 AM, Rui Paulo wrote: > > On 24 Jul 2010, at 14:53, Alexander Motin wrote: > >> Hi. >> >> I've make small observations of Intel TurboBoost technology under >> FreeBSD. This technology allows Intel Core i5/i7 CPUs to rise frequency >> of some cores if other cores are idle and power/thermal conditions >> permit. CPU core counted as idle, if it has been put into C3 or deeper >> power state (may reflect ACPI C2/C3 states). So to reach maximal >> effectiveness, some tuning may be needed. >> >> Here is my test case: FreeBSD 9-CURRENT on Core i5 650 CPU, 3.2GHz + 1/2 >> TurboBoost steps (+133/+266MHz) with boxed cooler at the open air. I was >> measuring building time of the net/mpd5 from sources, using only one CPU >> core (cpuset -l 0 time make). >> >> Untuned system (hz=3D1000): =A0 =A0 14.15 sec >> Enabled ACPI C2 (hz=3D1000+C2): 13.85 sec >> Enabled ACPI C3 (hz=3D1000+C3): 13.91 sec >> Reduced HZ (hz=3D100): =A0 =A0 =A0 =A0 =A014.16 sec >> Enabled ACPI C2 (hz=3D100+C2): =A013.85 sec >> Enabled ACPI C3 (hz=3D100+C3): =A013.86 sec >> Timers tuned* (hz=3D100): =A0 =A0 =A0 14.10 sec >> Enabled ACPI C2 (hz=3D100+C2): =A013.71 sec >> Enabled ACPI C3 (hz=3D100+C3): =A013.73 sec >> >> All numbers tested few times and are repeatable up to +/-0.01sec. >> >> *) Timers were tuned to reduce interrupt rates and respectively increase >> idle cores sleep time. These lines were added to loader.conf: >> sysctl kern.eventtimer.timer1=3Di8254 >> sysctl kern.eventtimer.timer2=3DNONE >> kern.eventtimer.singlemul=3D1 >> kern.hz=3D"100" >> >> PS: In this case benefit is small, but it is the least that can be >> achieved, depending on CPU model. Some models allow frequency to be >> risen by up to 6 steps (+798MHz). > > The numbers that you are showing doesn't show much difference. Have you t= ried buildworld? Agreed. The numbers are small enough that there could be a large degree of variation just based on environmental factors alone; there are other things that go into that as well, such as disk I/O, etc, that probably shouldn't be factored into a CPU performance test. Thanks, -Garrett