From patchwork Thu Feb 4 17:25:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 377343 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 BEB1FC433E6 for ; Thu, 4 Feb 2021 17:37:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A231864F60 for ; Thu, 4 Feb 2021 17:37:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238663AbhBDRgu (ORCPT ); Thu, 4 Feb 2021 12:36:50 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:50188 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238635AbhBDRgO (ORCPT ); Thu, 4 Feb 2021 12:36:14 -0500 Received: from 89-64-81-64.dynamic.chello.pl (89.64.81.64) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.537) id 4257cd42a0606640; Thu, 4 Feb 2021 18:35:00 +0100 From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Linux ACPI , Peter Zijlstra , Srinivas Pandruvada , Viresh Kumar , Giovanni Gherdovich , Mel Gorman , Michael Larabel , Juri Lelli , Vincent Guittot Subject: [PATCH v1 1/2] cpufreq: ACPI: Extend frequency tables to cover boost frequencies Date: Thu, 04 Feb 2021 18:25:37 +0100 Message-ID: <8467867.3EdU9UaQ17@kreacher> In-Reply-To: <13690581.X0sz4iL7V8@kreacher> References: <13690581.X0sz4iL7V8@kreacher> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki A severe performance regression on AMD EPYC processors when using the schedutil scaling governor was discovered by Phoronix.com and attributed to the following commits: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems") 976df7e5730e ("x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC") The source of the problem is that the maximum performance level taken for computing the arch_max_freq_ratio value used in the x86 scale- invariance code is higher than the one corresponding to the cpuinfo.max_freq value coming from the acpi_cpufreq driver. This effectively causes the scale-invariant utilization to fall below 100% even if the CPU runs at cpuinfo.max_freq or slightly faster, so the schedutil governor selects a frequency below cpuinfo.max_freq then. That frequency corresponds to a frequency table entry below the maximum performance level necessary to get to the "boost" range of CPU frequencies. However, if the cpuinfo.max_freq value coming from acpi_cpufreq was higher, the schedutil governor would select higher frequencies which in turn would allow acpi_cpufreq to set more adequate performance levels and to get to the "boost" range of CPU frequencies more often. This issue affects any systems where acpi_cpufreq is used and the "boost" (or "turbo") frequencies are enabled, not just AMD EPYC. Moreover, commit db865272d9c4 ("cpufreq: Avoid configuring old governors as default with intel_pstate") from the 5.10 development cycle made it extremely easy to default to schedutil even if the preferred driver is acpi_cpufreq as long as intel_pstate is built too, because the mere presence of the latter effectively removes the ondemand governor from the defaults. Distro kernels are likely to include both intel_pstate and acpi_cpufreq on x86, so their users who cannot use intel_pstate or choose to use acpi_cpufreq may easily be affectecd by this issue. To address this issue, extend the frequency table constructed by acpi_cpufreq for each CPU to cover the entire range of available frequencies (including the "boost" ones) if CPPC is available and indicates that "boost" (or "turbo") frequencies are enabled. That causes cpuinfo.max_freq to become the maximum "boost" frequency of the given CPU (instead of the maximum frequency returned by the ACPI _PSS object that corresponds to the "nominal" performance level). Fixes: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems") Fixes: 976df7e5730e ("x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC") Fixes: db865272d9c4 ("cpufreq: Avoid configuring old governors as default with intel_pstate") Link: https://www.phoronix.com/scan.php?page=article&item=linux511-amd-schedutil&num=1 Link: https://lore.kernel.org/linux-pm/20210203135321.12253-2-ggherdovich@suse.cz/ Reported-by: Michael Larabel Diagnosed-by: Giovanni Gherdovich Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/acpi-cpufreq.c | 107 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 95 insertions(+), 12 deletions(-) Index: linux-pm/drivers/cpufreq/acpi-cpufreq.c =================================================================== --- linux-pm.orig/drivers/cpufreq/acpi-cpufreq.c +++ linux-pm/drivers/cpufreq/acpi-cpufreq.c @@ -26,6 +26,7 @@ #include #include +#include #include #include @@ -53,6 +54,7 @@ struct acpi_cpufreq_data { unsigned int resume; unsigned int cpu_feature; unsigned int acpi_perf_cpu; + unsigned int first_perf_state; cpumask_var_t freqdomain_cpus; void (*cpu_freq_write)(struct acpi_pct_register *reg, u32 val); u32 (*cpu_freq_read)(struct acpi_pct_register *reg); @@ -221,10 +223,10 @@ static unsigned extract_msr(struct cpufr perf = to_perf_data(data); - cpufreq_for_each_entry(pos, policy->freq_table) + cpufreq_for_each_entry(pos, policy->freq_table + data->first_perf_state) if (msr == perf->states[pos->driver_data].status) return pos->frequency; - return policy->freq_table[0].frequency; + return policy->freq_table[data->first_perf_state].frequency; } static unsigned extract_freq(struct cpufreq_policy *policy, u32 val) @@ -363,6 +365,7 @@ static unsigned int get_cur_freq_on_cpu( struct cpufreq_policy *policy; unsigned int freq; unsigned int cached_freq; + unsigned int state; pr_debug("%s (%d)\n", __func__, cpu); @@ -374,7 +377,11 @@ static unsigned int get_cur_freq_on_cpu( if (unlikely(!data || !policy->freq_table)) return 0; - cached_freq = policy->freq_table[to_perf_data(data)->state].frequency; + state = to_perf_data(data)->state; + if (state < data->first_perf_state) + state = data->first_perf_state; + + cached_freq = policy->freq_table[state].frequency; freq = extract_freq(policy, get_cur_val(cpumask_of(cpu), data)); if (freq != cached_freq) { /* @@ -628,16 +635,54 @@ static int acpi_cpufreq_blacklist(struct } #endif +#ifdef CONFIG_ACPI_CPPC_LIB +static u64 get_max_boost_ratio(unsigned int cpu) +{ + struct cppc_perf_caps perf_caps; + u64 highest_perf, nominal_perf; + int ret; + + if (acpi_pstate_strict) + return 0; + + ret = cppc_get_perf_caps(cpu, &perf_caps); + if (ret) { + pr_debug("CPU%d: Unable to get performance capabilities (%d)\n", + cpu, ret); + return 0; + } + + highest_perf = perf_caps.highest_perf; + nominal_perf = perf_caps.nominal_perf; + + if (!highest_perf || !nominal_perf) { + pr_debug("CPU%d: highest or nominal performance missing\n", cpu); + return 0; + } + + if (highest_perf < nominal_perf) { + pr_debug("CPU%d: nominal performance above highest\n", cpu); + return 0; + } + + return div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf); +} +#else +static inline u64 get_max_boost_ratio(unsigned int cpu) { return 0; } +#endif + static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) { - unsigned int i; - unsigned int valid_states = 0; - unsigned int cpu = policy->cpu; + struct cpufreq_frequency_table *freq_table; + struct acpi_processor_performance *perf; struct acpi_cpufreq_data *data; + unsigned int cpu = policy->cpu; + struct cpuinfo_x86 *c = &cpu_data(cpu); + unsigned int valid_states = 0; unsigned int result = 0; - struct cpuinfo_x86 *c = &cpu_data(policy->cpu); - struct acpi_processor_performance *perf; - struct cpufreq_frequency_table *freq_table; + unsigned int state_count; + u64 max_boost_ratio; + unsigned int i; #ifdef CONFIG_SMP static int blacklisted; #endif @@ -750,8 +795,20 @@ static int acpi_cpufreq_cpu_init(struct goto err_unreg; } - freq_table = kcalloc(perf->state_count + 1, sizeof(*freq_table), - GFP_KERNEL); + state_count = perf->state_count + 1; + + max_boost_ratio = get_max_boost_ratio(cpu); + if (max_boost_ratio) { + /* + * Make a room for one more entry to represent the highest + * available "boost" frequency. + */ + state_count++; + valid_states++; + data->first_perf_state = valid_states; + } + + freq_table = kcalloc(state_count, sizeof(*freq_table), GFP_KERNEL); if (!freq_table) { result = -ENOMEM; goto err_unreg; @@ -785,6 +842,30 @@ static int acpi_cpufreq_cpu_init(struct valid_states++; } freq_table[valid_states].frequency = CPUFREQ_TABLE_END; + + if (max_boost_ratio) { + unsigned int state = data->first_perf_state; + unsigned int freq = freq_table[state].frequency; + + /* + * Because the loop above sorts the freq_table entries in the + * descending order, freq is the maximum frequency in the table. + * Assume that it corresponds to the CPPC nominal frequency and + * use it to populate the frequency field of the extra "boost" + * frequency entry. + */ + freq_table[0].frequency = freq * max_boost_ratio >> SCHED_CAPACITY_SHIFT; + /* + * The purpose of the extra "boost" frequency entry is to make + * the rest of cpufreq aware of the real maximum frequency, but + * the way to request it is the same as for the first_perf_state + * entry that is expected to cover the entire range of "boost" + * frequencies of the CPU, so copy the driver_data value from + * that entry. + */ + freq_table[0].driver_data = freq_table[state].driver_data; + } + policy->freq_table = freq_table; perf->state = 0; @@ -858,8 +939,10 @@ static void acpi_cpufreq_cpu_ready(struc { struct acpi_processor_performance *perf = per_cpu_ptr(acpi_perf_data, policy->cpu); + struct acpi_cpufreq_data *data = policy->driver_data; + unsigned int freq = policy->freq_table[data->first_perf_state].frequency; - if (perf->states[0].core_frequency * 1000 != policy->cpuinfo.max_freq) + if (perf->states[0].core_frequency * 1000 != freq) pr_warn(FW_WARN "P-state 0 is not max freq\n"); } From patchwork Thu Feb 4 17:34:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 376629 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 6BEE6C433E9 for ; Thu, 4 Feb 2021 17:37:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 286F164F60 for ; Thu, 4 Feb 2021 17:37:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238340AbhBDRhe (ORCPT ); Thu, 4 Feb 2021 12:37:34 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:53272 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238634AbhBDRgL (ORCPT ); Thu, 4 Feb 2021 12:36:11 -0500 Received: from 89-64-81-64.dynamic.chello.pl (89.64.81.64) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.537) id de86f543d15ab5d9; Thu, 4 Feb 2021 18:34:58 +0100 From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Linux ACPI , Peter Zijlstra , Srinivas Pandruvada , Viresh Kumar , Giovanni Gherdovich , Mel Gorman , Michael Larabel , Juri Lelli , Vincent Guittot Subject: [PATCH v1 2/2] cpufreq: ACPI: Update arch scale-invariance max perf ratio if CPPC is not there Date: Thu, 04 Feb 2021 18:34:32 +0100 Message-ID: <9510730.kuOQ4KzHjt@kreacher> In-Reply-To: <13690581.X0sz4iL7V8@kreacher> References: <13690581.X0sz4iL7V8@kreacher> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki If the maximum performance level taken for computing the arch_max_freq_ratio value used in the x86 scale-invariance code is higher than the one corresponding to the cpuinfo.max_freq value coming from the acpi_cpufreq driver, the scale-invariant utilization falls below 100% even if the CPU runs at cpuinfo.max_freq or slightly faster, which causes the schedutil governor to select a frequency below cpuinfo.max_freq. That frequency corresponds to a frequency table entry below the maximum performance level necessary to get to the "boost" range of CPU frequencies which prevents "boost" frequencies from being used in some workloads. While this issue is related to scale-invariance, it may be amplified by commit db865272d9c4 ("cpufreq: Avoid configuring old governors as default with intel_pstate") from the 5.10 development cycle which made it extremely easy to default to schedutil even if the preferred driver is acpi_cpufreq as long as intel_pstate is built too, because the mere presence of the latter effectively removes the ondemand governor from the defaults. Distro kernels are likely to include both intel_pstate and acpi_cpufreq on x86, so their users who cannot use intel_pstate or choose to use acpi_cpufreq may easily be affectecd by this issue. If CPPC is available, it can be used to address this issue by extending the frequency tables created by acpi_cpufreq to cover the entire available frequency range (including "boost" frequencies) for each CPU, but if CPPC is not there, acpi_cpufreq has no idea what the maximum "boost" frequency is and the frequency tables created by it cannot be extended in a meaningful way, so in that case make it ask the arch scale-invariance code to to use the "nominal" performance level for CPU utilization scaling in order to avoid the issue at hand. Fixes: db865272d9c4 ("cpufreq: Avoid configuring old governors as default with intel_pstate") Signed-off-by: Rafael J. Wysocki Reviewed-by: Giovanni Gherdovich Acked-by: Peter Zijlstra (Intel) --- arch/x86/kernel/smpboot.c | 1 + drivers/cpufreq/acpi-cpufreq.c | 8 ++++++++ 2 files changed, 9 insertions(+) Index: linux-pm/drivers/cpufreq/acpi-cpufreq.c =================================================================== --- linux-pm.orig/drivers/cpufreq/acpi-cpufreq.c +++ linux-pm/drivers/cpufreq/acpi-cpufreq.c @@ -806,6 +806,14 @@ static int acpi_cpufreq_cpu_init(struct state_count++; valid_states++; data->first_perf_state = valid_states; + } else { + /* + * If the maximum "boost" frequency is unknown, ask the arch + * scale-invariance code to use the "nominal" performance for + * CPU utilization scaling so as to prevent the schedutil + * governor from selecting inadequate CPU frequencies. + */ + arch_set_max_freq_ratio(true); } freq_table = kcalloc(state_count, sizeof(*freq_table), GFP_KERNEL); Index: linux-pm/arch/x86/kernel/smpboot.c =================================================================== --- linux-pm.orig/arch/x86/kernel/smpboot.c +++ linux-pm/arch/x86/kernel/smpboot.c @@ -1833,6 +1833,7 @@ void arch_set_max_freq_ratio(bool turbo_ arch_max_freq_ratio = turbo_disabled ? SCHED_CAPACITY_SCALE : arch_turbo_freq_ratio; } +EXPORT_SYMBOL_GPL(arch_set_max_freq_ratio); static bool turbo_disabled(void) {