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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 67173C433E0 for ; Thu, 9 Jul 2020 21:01:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3918720672 for ; Thu, 9 Jul 2020 21:01:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=telus.net header.i=@telus.net header.b="C4zOU/O3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726324AbgGIVBT (ORCPT ); Thu, 9 Jul 2020 17:01:19 -0400 Received: from cmta17.telus.net ([209.171.16.90]:53813 "EHLO cmta17.telus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726196AbgGIVBS (ORCPT ); Thu, 9 Jul 2020 17:01:18 -0400 Received: from dougxps ([173.180.45.4]) by cmsmtp with SMTP id tdfMjniArYgvrtdfNjUXWn; Thu, 09 Jul 2020 15:01:15 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=telus.net; s=neo; t=1594328475; bh=DO1Bu4NVVoKXFJHl4WRTu15YNf8zO2Urudde2JxqiC8=; h=From:To:Cc:References:In-Reply-To:Subject:Date; b=C4zOU/O3yx44XMRv35z8PHjCaLmnD5r7pb88Sto4Ohe6KkEz+xdWC0tEfu59EuTZ4 +diYDwHvSuLSOZCytzGQxWM0mF9jSqYtcoks+x+nmXiwEEAQ2cEYrNlMknVAp//RGw O0ovoppc+NTt5gxX33LQvy8TD/HqBdSFsfpc6pr8bZpZjZd6sKyqIwi5YfG5x2ta/u mMG9in4vpqPNdtc2fj4w6l4KXR0G2t7AeI6wQs5ZGCGi4ojlHK6MLN0fXIADAB3wIs /HZE1e7nXJswRBAiFfn8/a6zj7L1BrACM5Ilawc27Gvbw+F8rKm2qAtz93n8eK5CjA gx/hcxJyquWJg== X-Telus-Authed: none X-Authority-Analysis: v=2.3 cv=MIQeZ/Rl c=1 sm=1 tr=0 a=zJWegnE7BH9C0Gl4FFgQyA==:117 a=zJWegnE7BH9C0Gl4FFgQyA==:17 a=Pyq9K9CWowscuQLKlpiwfMBGOR0=:19 a=kj9zAlcOel0A:10 a=QyXUC8HyAAAA:8 a=zMdRSeC2V0WUCyk-5DIA:9 a=7Zwj6sZBwVKJAoWSPKxL6X1jA+E=:19 a=CjuIK1q_8ugA:10 From: "Doug Smythies" To: "'Rafael J. Wysocki'" Cc: "'Srinivas Pandruvada'" , "'LKML'" , "'Rafael J. Wysocki'" , "'Viresh Kumar'" , "'Giovanni Gherdovich'" , "'Linux PM'" References: <2016232.ihCVsphvri@kreacher> <2988949.NgUrjYMkJj@kreacher> In-Reply-To: <2988949.NgUrjYMkJj@kreacher> Subject: RE: [PATCH 2/2] cpufreq: intel_pstate: Use passive mode by default without HWP Date: Thu, 9 Jul 2020 14:01:11 -0700 Message-ID: <000801d65634$14f0ecb0$3ed2c610$@net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Content-Language: en-ca Thread-Index: AdYFAJargBggJ0TwR7qfhutpuszfMhRKzmYA X-CMAE-Envelope: MS4wfFH9BkYFuVxjO56y8+N3Ib/kkgigvoFuwtSboGqrttZaQE488zlSPJzRQlPGcCGGuMCEUEQKYGj6fkyXedT/ukZxD254yCs1DavUvyWAy2689+fu9Lgj m3xHlM7CKmH1BAylD5dLGXco8HrI9ri/eQd1b1zPmAjeIOqOUAJU7hO+iORuwlvSjdcPLFCtRjklPfgXSlzm94m+FdJatqbEcKqXD3WsKrBpI/DjJoDGZY+M bD8FK+YAn8mU4dat+RRr0zNVN6hgJco1iyMN5G2SZT1n24wpJe1+0kMDowY0EzTPPHUAbCrb5DCzsr+QM889C5yOuQMMYcQKgtPPv1MKgaLmY6EIYDHwuL6C ubMbIIqg5MmPsCX05i0anDYokXSPiA== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rafael, As you may or may not recall, I am attempting to untangle and separate multiple compounding issues around the intel_pstate driver and HWP (or not). Until everything is figured out, I am using the following rules: . never use x86_energy_perf_policy. . For HWP disabled: never change from active to passive or via versa, but rather do it via boot. . after boot always check and reset the various power limit log bits that are set. . never compile the kernel (well, until after any tests), which will set those bits again. . never run prime95 high heat torture test, which will set those bits again. . try to never do anything else that will set those bits again. On 2020.03.28 05:58 Rafael J. Wysocki wrote: > > From: "Rafael J. Wysocki" > > After recent changes allowing scale-invariant utilization to be > used on x86, the schedutil governor on top of intel_pstate in the > passive mode should be on par with (or better than) the active mode > "powersave" algorithm of intel_pstate on systems in which > hardware-managed P-states (HWP) are not used, so it should not be > necessary to use the internal scaling algorithm in those cases. > > Accordingly, modify intel_pstate to start in the passive mode by > default if the processor at hand does not support HWP of if the driver > is requested to avoid using HWP through the kernel command line. > > Among other things, that will allow utilization clamps and the > support for RT/DL tasks in the schedutil governor to be utilized on > systems in which intel_pstate is used. > > Signed-off-by: Rafael J. Wysocki > --- > Documentation/admin-guide/pm/intel_pstate.rst | 32 ++++++++++++++++----------- > drivers/cpufreq/intel_pstate.c | 3 ++- > 2 files changed, 21 insertions(+), 14 deletions(-) > > diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin- > guide/pm/intel_pstate.rst > index ad392f3aee06..39d80bc29ccd 100644 > --- a/Documentation/admin-guide/pm/intel_pstate.rst > +++ b/Documentation/admin-guide/pm/intel_pstate.rst > @@ -62,9 +62,10 @@ on the capabilities of the processor. > Active Mode > ----------- > > -This is the default operation mode of ``intel_pstate``. If it works in this > -mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` > -policies contains the string "intel_pstate". > +This is the default operation mode of ``intel_pstate`` for processors with > +hardware-managed P-states (HWP) support. If it works in this mode, the > +``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies > +contains the string "intel_pstate". > > In this mode the driver bypasses the scaling governors layer of ``CPUFreq`` and > provides its own scaling algorithms for P-state selection. Those algorithms > @@ -138,12 +139,13 @@ internal P-state selection logic to be less performance-focused. > Active Mode Without HWP > ~~~~~~~~~~~~~~~~~~~~~~~ > > -This is the default operation mode for processors that do not support the HWP > -feature. It also is used by default with the ``intel_pstate=no_hwp`` argument > -in the kernel command line. However, in this mode ``intel_pstate`` may refuse > -to work with the given processor if it does not recognize it. [Note that > -``intel_pstate`` will never refuse to work with any processor with the HWP > -feature enabled.] > +This operation mode is optional for processors that do not support the HWP > +feature or when the ``intel_pstate=no_hwp`` argument is passed to the kernel in > +the command line. The active mode is used in those cases if the > +``intel_pstate=active`` argument is passed to the kernel in the command line. ??? I can not see anywhere in the code where the kernel command line argument "intel_pstate=active" is dealt with. > +In this mode ``intel_pstate`` may refuse to work with processors that are not > +recognized by it. [Note that ``intel_pstate`` will never refuse to work with > +any processor with the HWP feature enabled.] > > In this mode ``intel_pstate`` registers utilization update callbacks with the > CPU scheduler in order to run a P-state selection algorithm, either > @@ -188,10 +190,14 @@ is not set. > Passive Mode > ------------ > > -This mode is used if the ``intel_pstate=passive`` argument is passed to the > -kernel in the command line (it implies the ``intel_pstate=no_hwp`` setting too). > -Like in the active mode without HWP support, in this mode ``intel_pstate`` may > -refuse to work with the given processor if it does not recognize it. > +This is the default operation mode of ``intel_pstate`` for processors without > +hardware-managed P-states (HWP) support. It is always used if the > +``intel_pstate=passive`` argument is passed to the kernel in the command line > +regardless of whether or not the given processor supports HWP. [Note that the > +``intel_pstate=no_hwp`` setting implies ``intel_pstate=passive`` if it is used > +without ``intel_pstate=active``.] ??? as above. I can not see where intel_pstate=active is dealt with in the code. > Like in the active mode without HWP support, > +in this mode ``intel_pstate`` may refuse to work with processors that are not > +recognized by it. > > If the driver works in this mode, the ``scaling_driver`` policy attribute in > ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_cpufreq". > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index d2297839374d..b24a5c5ec4f9 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -2769,6 +2769,8 @@ static int __init intel_pstate_init(void) > pr_info("Invalid MSRs\n"); > return -ENODEV; > } > + /* Without HWP start in the passive mode. */ > + default_driver = &intel_cpufreq; > > hwp_cpu_matched: > /* > @@ -2814,7 +2816,6 @@ static int __init intel_pstate_setup(char *str) > if (!strcmp(str, "disable")) { > no_load = 1; > } else if (!strcmp(str, "passive")) { > - pr_info("Passive mode enabled\n"); > default_driver = &intel_cpufreq; > no_hwp = 1; > } > -- > 2.16.4 Example 1: i5-9600k (hwp capable) (kernel 5.8-rc4): Grub: GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 consoleblank=450 intel_pstate=active intel_pstate=no_hwp cpuidle_sysfs_switch cpuidle.governor=teo" /proc/cmdline: BOOT_IMAGE=/boot/vmlinuz-5.8.0-rc4-stock root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 consoleblank=450 intel_pstate=active intel_pstate=no_hwp cpuidle_sysfs_switch cpuidle.governor=teo Result: doug@s18:~$ grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu1/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu2/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu3/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu4/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu5/cpufreq/scaling_driver:intel_cpufreq Example 2: i7-2600k (does not have hwp) (kernel 5.8-rc1) Grub: GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 consoleblank=300 intel_pstate=active cpuidle_sysfs_switch cpuidle.governor=teo" /proc/cmdline: BOOT_IMAGE=/boot/vmlinuz-5.8.0-rc1-stock root=UUID=bcbc624b-892b-46ca-9e9e-102daf644170 ro ipv6.disable=1 consoleblank=300 intel_pstate=active cpuidle_sysfs_switch cpuidle.governor=teo Result: doug@s15:~$ grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu1/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu2/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu3/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu4/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu5/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu6/cpufreq/scaling_driver:intel_cpufreq /sys/devices/system/cpu/cpu7/cpufreq/scaling_driver:intel_cpufreq ... Doug