From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA184C31E4A for ; Thu, 13 Jun 2019 16:33:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9965620449 for ; Thu, 13 Jun 2019 16:33:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732763AbfFMQdH (ORCPT ); Thu, 13 Jun 2019 12:33:07 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:42736 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730836AbfFMIMC (ORCPT ); Thu, 13 Jun 2019 04:12:02 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 8539480343; Thu, 13 Jun 2019 10:11:48 +0200 (CEST) Date: Thu, 13 Jun 2019 10:11:58 +0200 From: Pavel Machek To: Doug Smythies Cc: "'Rafael J. Wysocki'" , 'kernel list' , 'ACPI Devel Maling List' , "'Zhang, Rui'" , "'Rafael J. Wysocki'" , 'Viresh Kumar' , 'Linux PM' , 'Thomas Gleixner' , 'Ingo Molnar' , 'Borislav Petkov' , "'H. Peter Anvin'" , 'the arch/x86 maintainers' Subject: Re: 5.2-rc2: low framerate in flightgear, cpu not running at full speed, thermal related? Message-ID: <20190613081158.GA6853@amd> References: <20190609111732.GA2885@amd> <007701d520c7$c397bda0$4ac738e0$@net> <008f01d52178$07b3be70$171b3b50$@net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="PNTmBPCT7hxwcZjr" Content-Disposition: inline In-Reply-To: <008f01d52178$07b3be70$171b3b50$@net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org --PNTmBPCT7hxwcZjr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > On 2019.06.12 14:25 Rafael J. Wysocki wrote: > > On Wed, Jun 12, 2019 at 4:45 AM Doug Smythies wro= te: > >> > >> So, currently there seems to be 3 issues in this thread > >> (and I am guessing a little, without definitive data): > >> > >> 1.) On your system Kernel 5.4-rc2 (or 4) defaults to the intel_pstate = CPU frequency > >> scaling driver and the powersave governor, but kernel 4.6 defaults to = the > >> acpi-cpufreq CPU frequency scaling driver and the ondemand governor. > > > > Which means that intel_pstate works in the active mode by default and > > so it uses its internal governor. >=20 > Note sure what you mean by "internal governor"? > If you meant HWP (Hardware P-state), Pavel's processor doesn't have it. > If you meant the active powersave governor code within the driver, then a= greed. >=20 > > That governor is more performance-oriented than ondemand and it very > > well may cause more power to be allocated for the processor - at the > > expense of the GPU. >=20 > O.K. I mainly use servers and so have no experience with possible GPU > verses CPU tradeoffs. >=20 > However, I did re-do my tests measuring energy instead of CPU frequency > and found very little difference between the acpi-cpufreq/ondemand verses > intel_pstate/powersave as a function of single threaded load. Actually, > I did the test twice, one at 20 hertz work/sleep frequency and also > at 67 hertz work/sleep frequency. (Of course, Pavel's processor might > well have a different curve, but it is a similar vintage to mine > i5-2520M verses i7-2600K.) The worst difference was approximately > 1.1 extra processor package watts (an extra 5.5%) in the 80% to 85% > single threaded load range at 67 hertz work/sleep frequency for > the intel-pstate/powersave driver/governor.=20 >=20 > What am I saying? For a fixed amount of work to do per work/sleep cycle > (i.e. maybe per video frame related type work) while the CPU frequency Ve= rses load > curves might differ, the resulting processor energy curve differs much le= ss. > (i.e. the extra power for higher CPU frequency is for less time because i= t gets > the job done faster.) So, myself, I don't yet understand why only the one= method > would have hit thermal throttling, but not the other (if indeed it > doesn't). It seems there are serious differences in reporting :-(. How do I determine which frequency CPU really runs at, in 4.6 kernel? But it seems that your assumptions are incorrect for my workload. flightgear is single-threaded, and in my configuration saturates the CPU, because it would like to achieve higher framerate than my system is capable of. > Just for information: CPU frequency verses single threaded load curves > for the conservative governor is quite different between the two drivers. > (tests done in February, perhaps I should re-do and also look at energy > at the same time, or instead of CPU frequency.) So this might be my problem? Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --PNTmBPCT7hxwcZjr Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl0CBU4ACgkQMOfwapXb+vIA2ACgosp1TsX5OkrWOaRWttdwzNPP S8EAoI+okCL2bRqt3AKPFbSPngilmwwC =fxjZ -----END PGP SIGNATURE----- --PNTmBPCT7hxwcZjr--