From owner-freebsd-performance@FreeBSD.ORG Mon Jul 26 14:12:26 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 BB2C11065673; Mon, 26 Jul 2010 14:12:26 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-fx0-f54.google.com (mail-fx0-f54.google.com [209.85.161.54]) by mx1.freebsd.org (Postfix) with ESMTP id 1BD528FC12; Mon, 26 Jul 2010 14:12:25 +0000 (UTC) Received: by fxm13 with SMTP id 13so119931fxm.13 for ; Mon, 26 Jul 2010 07:12:24 -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:cc:subject:references:in-reply-to :x-enigmail-version:content-type:content-transfer-encoding; bh=G7oTVotFxTUAVpJGOpyCve/ZLseePrYacSwaTC6aNno=; b=QbPZspZFmIbc++j9Ib4gbVezU1T2mNbNj99c/AOMgOMOH0K5BjnWEnBYVBPJ7VxOJ+ wLtBsL+xUntTjL0rTnDQKh3qRjIDkwGLs8MDru4PAGmPBrPm6K15ejm5lT1IMPkKnVAs K/mgn4DrCMuHg4SGSiLX8s0hn/V1ZqfEyUGhw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=Gzu6YNHAKGwISQKktLl7d04TmFpIszqfBmLdg+Y296sFpSZ0tbiMk6RHP+ZymPEhJL Jmrs/uPjH364K4syI3ULulkkGR57spgefllJNdIzPZaWDFZ0jJHd09UCEANPl3YLNmK/ PdhOu3tRT3+711/SFFJhM0HlVxJrwam4Jgc7o= Received: by 10.223.109.140 with SMTP id j12mr6505414fap.22.1280153544092; Mon, 26 Jul 2010 07:12:24 -0700 (PDT) Received: from mavbook2.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id w11sm1401657fao.13.2010.07.26.07.12.21 (version=SSLv3 cipher=RC4-MD5); Mon, 26 Jul 2010 07:12:22 -0700 (PDT) Sender: Alexander Motin Message-ID: <4C4D9779.8080505@FreeBSD.org> Date: Mon, 26 Jul 2010 17:11:05 +0300 From: Alexander Motin User-Agent: Thunderbird 2.0.0.23 (X11/20091212) MIME-Version: 1.0 To: Robert Watson References: <4C4AF046.40507@FreeBSD.org> <4C4B720A.6020802@FreeBSD.org> In-Reply-To: X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Mon, 26 Jul 2010 15:56:02 +0000 Cc: freebsd-hackers@freebsd.org, freebsd-performance@freebsd.org, Rui Paulo 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: Mon, 26 Jul 2010 14:12:26 -0000 Robert Watson wrote: > On Sun, 25 Jul 2010, Alexander Motin wrote: >>> The numbers that you are showing doesn't show much difference. Have >>> you tried buildworld? >> >> If you mean relative difference -- as I have told, it's mostly because >> of my CPU. It's maximal boost is 266MHz (8.3%), but 133MHz of them is >> enabled most of time if CPU is not overheated. It probably doesn't, as >> it works on clear table under air conditioner. So maximal effect I can >> expect on is 4.2%. In such situation 2.8% probably not so bad to >> illustrate that feature works and there is space for further >> improvements. If I had Core i5-750S I would expect 33% boost. > > Can I recommend the use of ministat(1) and sample sizes of at least 8 > runs per configuration? Thanks for pushing me to do it right. :) Here is 3*15 runs with fresh kernel with disabled debug. Results are quite close to original: -2.73% and -2.19% of time. x C1 + C2 * C3 +-----------------------------------------------------------------+ |+ * x | |+ * x | |+ * x | |+ * x | |+ * x | |+ * x | |+ * x | |+ ** x | |+ + ** xx | |+ + ** ** xx x| | |__M_A____| | |A| | | |A| | +-----------------------------------------------------------------+ N Min Max Median Avg Stddev x 15 12.68 12.84 12.69 12.698667 0.039254966 + 15 12.35 12.36 12.35 12.351333 0.0035186578 Difference at 95.0% confidence -0.347333 +/- 0.0208409 -2.7352% +/- 0.164119% (Student's t, pooled s = 0.0278687) * 15 12.41 12.44 12.42 12.42 0.0075592895 Difference at 95.0% confidence -0.278667 +/- 0.0211391 -2.19446% +/- 0.166467% (Student's t, pooled s = 0.0282674) I also checked one more aspect -- TurboBoost works only when CPU runs at highest EIST frequency (P0 state). I've reduced dev.cpu.0.freq from 3201 to 3067 and repeated the test: x C1 + C2 * C3 +-----------------------------------------------------------------+ | x + * | | x + * | | x + * | | x + * *| | x x + * *| | x x + + * *| | x x + + * *| | x x + + * *| | x x + + + + * *| ||MA| | | |_MA_| | | M_A_|| +-----------------------------------------------------------------+ N Min Max Median Avg Stddev x 15 13.72 13.73 13.72 13.723333 0.0048795004 + 15 13.79 13.82 13.8 13.803333 0.0072374686 Difference at 95.0% confidence 0.08 +/- 0.00461567 0.582949% +/- 0.0336337% (Student's t, pooled s = 0.00617213) * 15 13.89 13.9 13.89 13.894 0.0050709255 Difference at 95.0% confidence 0.170667 +/- 0.00372127 1.24362% +/- 0.0271164% (Student's t, pooled s = 0.00497613) In that case using C2 or C3 predictably caused small performance reduce, as after falling to sleep, CPU needs time to wakeup. Even if tested CPU0 won't ever sleep during test, it's TLB shutdown IPIs to other cores still probably could suffer from waiting other cores' wakeup. Obviously in first test these 0.58% and 1.24% were subtracted from the TurboBoost's maximal benefit of 4.3% on this CPU. -- Alexander Motin