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=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 260DBC4361B for ; Thu, 17 Dec 2020 14:21:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E25052389F for ; Thu, 17 Dec 2020 14:21:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728582AbgLQOVg (ORCPT ); Thu, 17 Dec 2020 09:21:36 -0500 Received: from mga01.intel.com ([192.55.52.88]:50332 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727385AbgLQOVf (ORCPT ); Thu, 17 Dec 2020 09:21:35 -0500 IronPort-SDR: DPRK4vC76mlpRcImIyYo/w5I86O9bK1Q6a+4Mirc8/V3q+Z/k6GaBxfM2Vlb9eNeXWRmHLuxYE v2v0eAWsJFpw== X-IronPort-AV: E=McAfee;i="6000,8403,9837"; a="193650969" X-IronPort-AV: E=Sophos;i="5.78,428,1599548400"; d="scan'208";a="193650969" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Dec 2020 06:19:22 -0800 IronPort-SDR: fOAH7ukgB26MJsFvhANElmPwBaaoiLsDLhTTvLtxkCq8qNiEcBZRoQdlDOoDr3/LopDYw0CZkZ j8ZxR6ZQ/Icg== X-IronPort-AV: E=Sophos;i="5.78,428,1599548400"; d="scan'208";a="342505216" Received: from apstasen-mobl.amr.corp.intel.com ([10.212.63.173]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Dec 2020 06:19:18 -0800 Message-ID: Subject: Re: [PATCH] cpufreq: intel_pstate: Use the latest guaranteed freq during verify From: Srinivas Pandruvada To: "Rafael J. Wysocki" Cc: Len Brown , "Rafael J. Wysocki" , Viresh Kumar , Linux PM , Linux Kernel Mailing List Date: Thu, 17 Dec 2020 06:19:13 -0800 In-Reply-To: References: <20201217104215.2544837-1-srinivas.pandruvada@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 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); + 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; Thanks, Srinivas > > > +               return max_state * cpu->pstate.scaling; > > +       } > >         return global.turbo_disabled || global.no_turbo ? > >                         cpu->pstate.max_freq : cpu- > > >pstate.turbo_freq; > >  } > > --