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=-14.0 required=3.0 tests=BAYES_00,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 91044C2BB9A for ; Thu, 17 Dec 2020 15:25:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4736823976 for ; Thu, 17 Dec 2020 15:25:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728844AbgLQPZQ (ORCPT ); Thu, 17 Dec 2020 10:25:16 -0500 Received: from mail-oi1-f178.google.com ([209.85.167.178]:37066 "EHLO mail-oi1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbgLQPZQ (ORCPT ); Thu, 17 Dec 2020 10:25:16 -0500 Received: by mail-oi1-f178.google.com with SMTP id l207so32600885oib.4; Thu, 17 Dec 2020 07:25:00 -0800 (PST) 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=yBjQ26tCp5kMsZ/5QoJhv6qF7gnzr2Vigl1CJcEuRds=; b=b6l85tsuRRRcrd69shwlMLZCzA+xZ34+R+vl72RQy0wlALd9ZE7DBqg1+7OS72xqU0 F2va3oiy51YtxUyEGd7y2tNC5PoiKLmBmXZWUNVessFs3vy+0JFkRHxxSePyHS/ujORB 968y1ij5xnRlsTwquO3+kqPB3KSGYbNGEL7YfJH7QKKFfPTX7TIgK8YpL6tjk6mMm7QJ g3RSr4vbGG3PtL4wqNOSoI4expxt1PYxB8l6IugXCVdk64oHFGqbzmlNnlVWVmD6WjPy qFA8gkpWg4g6UCZJHz9eKgilRYNK7O4AFacQiuON8BMUjxUVZO0G9OB40mPwEH+zeFMg spdw== X-Gm-Message-State: AOAM531MAvqr2CrnR9ooq3QZVci1AASGFU0zkXV6goXLjoCICas1PwMq CWp5rBLky5fMSDy5GMrDpr+qEgIfEtHgKZb3lwU= X-Google-Smtp-Source: ABdhPJxkU+0Ibu112oX+dEycvcCV9SDTS1bK3Cywgd14gtpkoFeN+N741dCkJZjBGI+ZXycPMDsZIRIim2cTCsQBWQM= X-Received: by 2002:aca:5a42:: with SMTP id o63mr4882042oib.69.1608218674759; Thu, 17 Dec 2020 07:24:34 -0800 (PST) MIME-Version: 1.0 References: <20201217104215.2544837-1-srinivas.pandruvada@linux.intel.com> <93d4eebb5121ad0497af555c55a6ad74b8a06e64.camel@linux.intel.com> <8153207.dYVdvtsJbe@kreacher> <6ef769aa04ee8e765863fd4af083eb85cdcb4827.camel@linux.intel.com> In-Reply-To: <6ef769aa04ee8e765863fd4af083eb85cdcb4827.camel@linux.intel.com> From: "Rafael J. Wysocki" Date: Thu, 17 Dec 2020 16:24:23 +0100 Message-ID: Subject: Re: [PATCH] cpufreq: intel_pstate: Use the latest guaranteed freq during verify To: Srinivas Pandruvada Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Len Brown , Viresh Kumar , Linux PM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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!