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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 64094C31E4A for ; Thu, 13 Jun 2019 15:55:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C2C221473 for ; Thu, 13 Jun 2019 15:55:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560441317; bh=GS7QM8uUKY06BkWq879HDS/Fiak3u2XFHTsSLPi6USA=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=LuMa8P0lD0H96OhDb3alJ7Jzz/fVF4fv9p3ZPTQ1747nANNz1bOEMBTYsZ4A9Qxmx AL3FuVmD4QZLtJuDbnF0PYoHyKsTyifMDXcn9K9Kf2UQKiVl2vp+I6nuiC3FxOw6/I clVyGT/TXIW1QhkFD1V5eEjf5l8yy7jtszJNpisc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732092AbfFMPzL (ORCPT ); Thu, 13 Jun 2019 11:55:11 -0400 Received: from mail-ot1-f44.google.com ([209.85.210.44]:40395 "EHLO mail-ot1-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731561AbfFMIxL (ORCPT ); Thu, 13 Jun 2019 04:53:11 -0400 Received: by mail-ot1-f44.google.com with SMTP id x24so18192548otp.7; Thu, 13 Jun 2019 01:53:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=FxA2TuQ76TdBmK7s0p6DMBbnrU5zVRKKjjHLZHr3Nrw=; b=Yxz1PrfEwG+xwQfQrX5q9OYleNmlcuAsJPTmLfQ7gVKEvAR+96Fjki1WJPeX8bRYQl HuR4VQZkg7hv4n6r23V00pi6LnVo5kXHsecCxBP5tGF79PKKtJ+fXOELR7U9Xt4GRTcn 9CibEfBsWSxilq23lhLLpqkO/T/ruOYn0f5G8II2BuQmEbATtOJRLLYf/F3ffTRGHZ3+ gEw4dPeWEqb5pqH2RXLQrDSD+JsZVYpGJfwbV+UDkfo69J3moMWNSLxkrqg0Q69sAM0Q kSLwi60ID8UTSnBe7YcyTgv6x11TvRIeUGBcEvFsTOyq2cknIxdlMJhByhe54Hz5xD7r Zk4Q== X-Gm-Message-State: APjAAAUi4EVEc8cS8f5ENKqe7SrlOIXGcr+dWSzNLyj01OZXWkDFETFk 1V3VZUet3YydJfMKSltr+DlIrJWwrHJHi+RAnHjviQ== X-Google-Smtp-Source: APXvYqyI1lj+Z+cGNfdobQgfAVNEbIpL2r7FCl8K1bHleKh5pVvYkSHmP3FF0kCptnpXUK5RHTkVoifYko+1nXHyn24= X-Received: by 2002:a9d:5f05:: with SMTP id f5mr36455415oti.167.1560415990521; Thu, 13 Jun 2019 01:53:10 -0700 (PDT) MIME-Version: 1.0 References: <20190609111732.GA2885@amd> <007701d520c7$c397bda0$4ac738e0$@net> <008f01d52178$07b3be70$171b3b50$@net> In-Reply-To: <008f01d52178$07b3be70$171b3b50$@net> From: "Rafael J. Wysocki" Date: Thu, 13 Jun 2019 10:52:57 +0200 Message-ID: Subject: Re: 5.2-rc2: low framerate in flightgear, cpu not running at full speed, thermal related? To: Doug Smythies Cc: "Rafael J. Wysocki" , Pavel Machek , 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" Content-Type: text/plain; charset="UTF-8" Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Thu, Jun 13, 2019 at 1:40 AM Doug Smythies wrote: > > On 2019.06.12 14:25 Rafael J. Wysocki wrote: > > On Wed, Jun 12, 2019 at 4:45 AM Doug Smythies wrote: > >> > >> 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. > > 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 agreed. That's what I mean. > > 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. > > O.K. I mainly use servers and so have no experience with possible GPU > verses CPU tradeoffs. > > 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. I see. Then this shouldn't matter. > 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 Verses load > curves might differ, the resulting processor energy curve differs much less. > (i.e. the extra power for higher CPU frequency is for less time because it 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). > Other differences between kernel 4.6 and 5.2-rc? might explain it. Right. I personally doubt that any thermal throttling is involved here. > I did all my tests on kernel 5.2-rc3, except that one example from kernel 4.4 on my > earlier reply, so that were not other variables than CPU scaling driver and > governor changes. > > > The lower-than-expected frame rate may result from that, in principle. > > > One way to mitigate that might be to use intel_pstate in the passive > > mode (pass intel_pstate=passive to the kernel in the command line) > > along with either ondemand or schedutil as the governor. > > The CPU frequency verses load curves for this those two governors are very similar > for both the acpi_cpufreq and intel_cpufreq (which is the intel_pstate driver > in passive mode) drivers. That's what I would expect. Cheers!