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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 88EFDC2BB9A for ; Thu, 17 Dec 2020 17:11:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 57F5D238E8 for ; Thu, 17 Dec 2020 17:11:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729038AbgLQRL1 (ORCPT ); Thu, 17 Dec 2020 12:11:27 -0500 Received: from mga17.intel.com ([192.55.52.151]:45840 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728166AbgLQRL1 (ORCPT ); Thu, 17 Dec 2020 12:11:27 -0500 IronPort-SDR: AXqjJkMVmSod+YFuUk9H0QQcwG573Z+Hty7Gctr5M/OKdwu7DpKm5yQ00X/RfsdChmUfY39DWr paBgbD7DMXkg== X-IronPort-AV: E=McAfee;i="6000,8403,9838"; a="155095028" X-IronPort-AV: E=Sophos;i="5.78,428,1599548400"; d="scan'208";a="155095028" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Dec 2020 09:09:40 -0800 IronPort-SDR: IIv2lq8TUBDy1DO7MKHYFV+wIVDzRw2TyyuZadvxxwV7eRLWrIfCtGYwKVFhGV6/ix7kPK/lhB qEf9OIlKbK4g== X-IronPort-AV: E=Sophos;i="5.78,428,1599548400"; d="scan'208";a="387646813" Received: from ejmar-mobl.amr.corp.intel.com ([10.254.182.236]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Dec 2020 09:09:31 -0800 Message-ID: <16328b6c4531e676f829601e72dee4a5c2f802a7.camel@linux.intel.com> Subject: Re: [PATCH] cpufreq: intel_pstate: Use the latest guaranteed freq during verify From: Srinivas Pandruvada To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Len Brown , Viresh Kumar , Linux PM , Linux Kernel Mailing List Date: Thu, 17 Dec 2020 09:09:19 -0800 In-Reply-To: References: <20201217104215.2544837-1-srinivas.pandruvada@linux.intel.com> <93d4eebb5121ad0497af555c55a6ad74b8a06e64.camel@linux.intel.com> <8153207.dYVdvtsJbe@kreacher> <6ef769aa04ee8e765863fd4af083eb85cdcb4827.camel@linux.intel.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.2 (3.38.2-1.fc33) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2020-12-17 at 16:24 +0100, Rafael J. Wysocki wrote: > On Thu, Dec 17, 2020 at 4:21 PM Srinivas Pandruvada > wrote: > > > > On Thu, 2020-12-17 at 16:12 +0100, Rafael J. Wysocki wrote: > > > On Thursday, December 17, 2020 3:23:44 PM CET Srinivas Pandruvada > > > wrote: > > > > On Thu, 2020-12-17 at 06:19 -0800, Srinivas Pandruvada wrote: > > > > > On Thu, 2020-12-17 at 14:58 +0100, Rafael J. Wysocki wrote: > > > > > > On Thu, Dec 17, 2020 at 11:44 AM Srinivas Pandruvada > > > > > > wrote: > > > > > > > > > > > > > > This change tries to address an issue, when BIOS disabled > > > > > > > turbo > > > > > > > but HWP_CAP guaranteed is changed later and user space > > > > > > > wants > > > > > > > to > > > > > > > take > > > > > > > advantage of this increased guaranteed performance. > > > > > > > > > > > > > > The HWP_CAP.GUARANTEED value is not a static value. It > > > > > > > can be > > > > > > > changed > > > > > > > by some out of band agent or during Intel Speed Select > > > > > > > performance > > > > > > > level change. The HWP_CAP.MAX still shows max possible > > > > > > > performance > > > > > > > when > > > > > > > BIOS disabled turbo. So guaranteed can still change as > > > > > > > long > > > > > > > as > > > > > > > this > > > > > > > is > > > > > > > same or below HWP_CAP.MAX. > > > > > > > > > > > > > > When guaranteed is changed, the sysfs base_frequency > > > > > > > attributes > > > > > > > shows > > > > > > > the latest guaranteed frequency. This attribute can be > > > > > > > used > > > > > > > by > > > > > > > user > > > > > > > space software to update scaling min/max frequency. > > > > > > > > > > > > > > Currently the setpolicy callback already uses the latest > > > > > > > HWP_CAP > > > > > > > values when setting HWP_REQ. But the verify callback will > > > > > > > still > > > > > > > restrict > > > > > > > the user settings to the to old guaranteed value. So if > > > > > > > the > > > > > > > guaranteed > > > > > > > is increased, user space can't take advantage of it. > > > > > > > > > > > > > > To solve this similar to setpolicy callback, read the > > > > > > > latest > > > > > > > HWP_CAP > > > > > > > values and use it to restrict the maximum setting. This > > > > > > > is > > > > > > > done > > > > > > > by > > > > > > > calling intel_pstate_get_hwp_max(), which already > > > > > > > accounts > > > > > > > for > > > > > > > user > > > > > > > and BIOS turbo disable to get the current max > > > > > > > performance. > > > > > > > > > > > > > > This issue is side effect of fixing the issue of scaling > > > > > > > frequency > > > > > > > limits by the > > > > > > >  'commit eacc9c5a927e ("cpufreq: intel_pstate: > > > > > > >  Fix intel_pstate_get_hwp_max() for turbo disabled")' > > > > > > > The fix resulted in correct setting of reduced scaling > > > > > > > frequencies, > > > > > > > but this resulted in capping HWP.REQ to > > > > > > > HWP_CAP.GUARANTEED in > > > > > > > this > > > > > > > case. > > > > > > > > > > > > > > Cc: 5.8+ # 5.8+ > > > > > > > Signed-off-by: Srinivas Pandruvada < > > > > > > > srinivas.pandruvada@linux.intel.com> > > > > > > > --- > > > > > > >  drivers/cpufreq/intel_pstate.c | 6 ++++++ > > > > > > >  1 file changed, 6 insertions(+) > > > > > > > > > > > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > > > > > > b/drivers/cpufreq/intel_pstate.c > > > > > > > index 2a4db856222f..7081d1edb22b 100644 > > > > > > > --- a/drivers/cpufreq/intel_pstate.c > > > > > > > +++ b/drivers/cpufreq/intel_pstate.c > > > > > > > @@ -2199,6 +2199,12 @@ static void > > > > > > > intel_pstate_clear_update_util_hook(unsigned int cpu) > > > > > > > > > > > > > >  static int intel_pstate_get_max_freq(struct cpudata > > > > > > > *cpu) > > > > > > >  { > > > > > > > +       if (hwp_active) { > > > > > > > +               int turbo_max, max_state; > > > > > > > + > > > > > > > +               intel_pstate_get_hwp_max(cpu->cpu, > > > > > > > &turbo_max, > > > > > > > &max_state); > > > > > > > > > > > > This would cause intel_pstate_get_hwp_max() to be called > > > > > > twice > > > > > > in > > > > > > intel_pstate_update_perf_limits() which is not perfect. > > > > > > > > > > We can optimize by using cached value. > > > > > > > > > > > > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > > > > b/drivers/cpufreq/intel_pstate.c > > > > > index 7081d1edb22b..d345c9ef240c 100644 > > > > > --- a/drivers/cpufreq/intel_pstate.c > > > > > +++ b/drivers/cpufreq/intel_pstate.c > > > > > @@ -2223,7 +2223,11 @@ static void > > > > > intel_pstate_update_perf_limits(struct cpudata *cpu, > > > > >          * rather than pure ratios. > > > > >          */ > > > > >         if (hwp_active) { > > > > > -               intel_pstate_get_hwp_max(cpu->cpu, > > > > > &turbo_max, > > > > > &max_state); > > > > > +               if (global.no_turbo || global.turbo_disabled) > > > > > +                       max_state = HWP_GUARANTEED_PERF(cpu- > > > > > > hwp_cap_cached); > > > > > +               else > > > > > +                       max_state = HWP_HIGHEST_PERF(cpu- > > > > > > hwp_cap_cached); > > > > Can use  ternary operator instead of if..else. to further > > > > simplify. > > > > > > > > > +               turbo_max = HWP_HIGHEST_PERF(cpu- > > > > > >hwp_cached); > > > > >         } else { > > > > >                 max_state = global.no_turbo || > > > > > global.turbo_disabled > > > > > ? > > > > >                         cpu->pstate.max_pstate : cpu- > > > > > > pstate.turbo_pstate; > > > > > > Well, would something like the patch below work? > > > > > > --- > > >  drivers/cpufreq/intel_pstate.c |   16 +++++++++++++--- > > >  1 file changed, 13 insertions(+), 3 deletions(-) > > > > > > Index: linux-pm/drivers/cpufreq/intel_pstate.c > > > ================================================================= > > > == > > > --- linux-pm.orig/drivers/cpufreq/intel_pstate.c > > > +++ linux-pm/drivers/cpufreq/intel_pstate.c > > > @@ -2207,9 +2207,9 @@ static void intel_pstate_update_perf_lim > > >                                             unsigned int > > > policy_min, > > >                                             unsigned int > > > policy_max) > > >  { > > > -       int max_freq = intel_pstate_get_max_freq(cpu); > > >         int32_t max_policy_perf, min_policy_perf; > > >         int max_state, turbo_max; > > > +       int max_freq; > > > > > >         /* > > >          * HWP needs some special consideration, because on BDX > > > the > > > @@ -2223,6 +2223,7 @@ static void intel_pstate_update_perf_lim > > >                         cpu->pstate.max_pstate : cpu- > > > > pstate.turbo_pstate; > > >                 turbo_max = cpu->pstate.turbo_pstate; > > >         } > > > +       max_freq = max_state * cpu->pstate.scaling; > > > > > >         max_policy_perf = max_state * policy_max / max_freq; > > >         if (policy_max == policy_min) { > > > @@ -2325,9 +2326,18 @@ static void intel_pstate_adjust_policy_m > > >  static void intel_pstate_verify_cpu_policy(struct cpudata *cpu, > > >                                            struct > > > cpufreq_policy_data > > > *policy) > > >  { > > > +       int max_freq; > > > + > > >         update_turbo_state(); > > > -       cpufreq_verify_within_limits(policy, policy- > > > > cpuinfo.min_freq, > > > -                                    > > > intel_pstate_get_max_freq(cpu)); > > > +       if (hwp_active) { > > > +               int max_state, turbo_max; > > > + > > > +               intel_pstate_get_hwp_max(cpu->cpu, &turbo_max, > > > &max_state); > > > +               max_freq = max_state * cpu->pstate.scaling; > > > +       } else { > > > +               max_freq = intel_pstate_get_max_freq(cpu); > > > +       } > > > +       cpufreq_verify_within_limits(policy, policy- > > > > cpuinfo.min_freq, max_freq); > > > > > >         intel_pstate_adjust_policy_max(cpu, policy); > > >  } > > > > > Should work. > >  I will test this patch and let you know once I get the system. > > Please do, thank you! This works. Please check if you can submit a change for this. Thanks, Srinivas