cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor
Future AMD processors, starting with Family 16h, can provide software with feedback on how the workload may respond to frequency change -- memory-bound workloads will not benefit from higher frequency, where as compute-bound workloads will. This patch enables this "frequency sensitivity feedback" to aid the ondemand governor to make better frequency change decisions by hooking into the powersave bias. Signed-off-by: Jacob Shin <jacob.shin@amd.com> Acked-by: Thomas Renninger <trenn@suse.de> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>hifive-unleashed-5.1
Jacob Shin
Rafael J. Wysocki
parent
fb30809efa
commit
9c5320c8ea
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@ -167,6 +167,27 @@ of load evaluation and helping the CPU stay at its top speed when truly
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busy, rather than shifting back and forth in speed. This tunable has no
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effect on behavior at lower speeds/lower CPU loads.
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powersave_bias: this parameter takes a value between 0 to 1000. It
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defines the percentage (times 10) value of the target frequency that
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will be shaved off of the target. For example, when set to 100 -- 10%,
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when ondemand governor would have targeted 1000 MHz, it will target
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1000 MHz - (10% of 1000 MHz) = 900 MHz instead. This is set to 0
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(disabled) by default.
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When AMD frequency sensitivity powersave bias driver --
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drivers/cpufreq/amd_freq_sensitivity.c is loaded, this parameter
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defines the workload frequency sensitivity threshold in which a lower
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frequency is chosen instead of ondemand governor's original target.
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The frequency sensitivity is a hardware reported (on AMD Family 16h
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Processors and above) value between 0 to 100% that tells software how
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the performance of the workload running on a CPU will change when
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frequency changes. A workload with sensitivity of 0% (memory/IO-bound)
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will not perform any better on higher core frequency, whereas a
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workload with sensitivity of 100% (CPU-bound) will perform better
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higher the frequency. When the driver is loaded, this is set to 400
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by default -- for CPUs running workloads with sensitivity value below
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40%, a lower frequency is chosen. Unloading the driver or writing 0
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will disable this feature.
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2.5 Conservative
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----------------
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@ -182,6 +182,7 @@
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#define X86_FEATURE_PTS (7*32+ 6) /* Intel Package Thermal Status */
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#define X86_FEATURE_DTHERM (7*32+ 7) /* Digital Thermal Sensor */
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#define X86_FEATURE_HW_PSTATE (7*32+ 8) /* AMD HW-PState */
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#define X86_FEATURE_PROC_FEEDBACK (7*32+ 9) /* AMD ProcFeedbackInterface */
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/* Virtualization flags: Linux defined, word 8 */
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#define X86_FEATURE_TPR_SHADOW (8*32+ 0) /* Intel TPR Shadow */
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@ -39,8 +39,9 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
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{ X86_FEATURE_APERFMPERF, CR_ECX, 0, 0x00000006, 0 },
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{ X86_FEATURE_EPB, CR_ECX, 3, 0x00000006, 0 },
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{ X86_FEATURE_XSAVEOPT, CR_EAX, 0, 0x0000000d, 1 },
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{ X86_FEATURE_CPB, CR_EDX, 9, 0x80000007, 0 },
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{ X86_FEATURE_HW_PSTATE, CR_EDX, 7, 0x80000007, 0 },
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{ X86_FEATURE_CPB, CR_EDX, 9, 0x80000007, 0 },
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{ X86_FEATURE_PROC_FEEDBACK, CR_EDX,11, 0x80000007, 0 },
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{ X86_FEATURE_NPT, CR_EDX, 0, 0x8000000a, 0 },
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{ X86_FEATURE_LBRV, CR_EDX, 1, 0x8000000a, 0 },
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{ X86_FEATURE_SVML, CR_EDX, 2, 0x8000000a, 0 },
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@ -129,6 +129,23 @@ config X86_POWERNOW_K8
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For details, take a look at <file:Documentation/cpu-freq/>.
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config X86_AMD_FREQ_SENSITIVITY
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tristate "AMD frequency sensitivity feedback powersave bias"
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depends on CPU_FREQ_GOV_ONDEMAND && X86_ACPI_CPUFREQ && CPU_SUP_AMD
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help
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This adds AMD-specific powersave bias function to the ondemand
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governor, which allows it to make more power-conscious frequency
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change decisions based on feedback from hardware (availble on AMD
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Family 16h and above).
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Hardware feedback tells software how "sensitive" to frequency changes
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the CPUs' workloads are. CPU-bound workloads will be more sensitive
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-- they will perform better as frequency increases. Memory/IO-bound
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workloads will be less sensitive -- they will not necessarily perform
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better as frequency increases.
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If in doubt, say N.
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config X86_GX_SUSPMOD
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tristate "Cyrix MediaGX/NatSemi Geode Suspend Modulation"
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depends on X86_32 && PCI
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@ -41,6 +41,7 @@ obj-$(CONFIG_X86_SPEEDSTEP_CENTRINO) += speedstep-centrino.o
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obj-$(CONFIG_X86_P4_CLOCKMOD) += p4-clockmod.o
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obj-$(CONFIG_X86_CPUFREQ_NFORCE2) += cpufreq-nforce2.o
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obj-$(CONFIG_X86_INTEL_PSTATE) += intel_pstate.o
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obj-$(CONFIG_X86_AMD_FREQ_SENSITIVITY) += amd_freq_sensitivity.o
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##################################################################################
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# ARM SoC drivers
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@ -0,0 +1,148 @@
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/*
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* amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
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* for the ondemand governor.
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*
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* Copyright (C) 2013 Advanced Micro Devices, Inc.
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*
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* Author: Jacob Shin <jacob.shin@amd.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/percpu-defs.h>
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#include <linux/init.h>
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#include <linux/mod_devicetable.h>
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#include <asm/msr.h>
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#include <asm/cpufeature.h>
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#include "cpufreq_governor.h"
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#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL 0xc0010080
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#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE 0xc0010081
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#define CLASS_CODE_SHIFT 56
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#define POWERSAVE_BIAS_MAX 1000
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#define POWERSAVE_BIAS_DEF 400
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struct cpu_data_t {
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u64 actual;
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u64 reference;
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unsigned int freq_prev;
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};
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static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);
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static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
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unsigned int freq_next,
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unsigned int relation)
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{
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int sensitivity;
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long d_actual, d_reference;
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struct msr actual, reference;
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struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
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struct dbs_data *od_data = policy->governor_data;
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struct od_dbs_tuners *od_tuners = od_data->tuners;
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struct od_cpu_dbs_info_s *od_info =
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od_data->cdata->get_cpu_dbs_info_s(policy->cpu);
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if (!od_info->freq_table)
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return freq_next;
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rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
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&actual.l, &actual.h);
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rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
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&reference.l, &reference.h);
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actual.h &= 0x00ffffff;
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reference.h &= 0x00ffffff;
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/* counter wrapped around, so stay on current frequency */
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if (actual.q < data->actual || reference.q < data->reference) {
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freq_next = policy->cur;
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goto out;
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}
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d_actual = actual.q - data->actual;
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d_reference = reference.q - data->reference;
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/* divide by 0, so stay on current frequency as well */
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if (d_reference == 0) {
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freq_next = policy->cur;
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goto out;
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}
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sensitivity = POWERSAVE_BIAS_MAX -
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(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
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clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
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/* this workload is not CPU bound, so choose a lower freq */
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if (sensitivity < od_tuners->powersave_bias) {
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if (data->freq_prev == policy->cur)
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freq_next = policy->cur;
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if (freq_next > policy->cur)
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freq_next = policy->cur;
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else if (freq_next < policy->cur)
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freq_next = policy->min;
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else {
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unsigned int index;
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cpufreq_frequency_table_target(policy,
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od_info->freq_table, policy->cur - 1,
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CPUFREQ_RELATION_H, &index);
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freq_next = od_info->freq_table[index].frequency;
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}
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data->freq_prev = freq_next;
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} else
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data->freq_prev = 0;
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out:
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data->actual = actual.q;
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data->reference = reference.q;
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return freq_next;
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}
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static int __init amd_freq_sensitivity_init(void)
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{
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u64 val;
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if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
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return -ENODEV;
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if (!static_cpu_has(X86_FEATURE_PROC_FEEDBACK))
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return -ENODEV;
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if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
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return -ENODEV;
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if (!(val >> CLASS_CODE_SHIFT))
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return -ENODEV;
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od_register_powersave_bias_handler(amd_powersave_bias_target,
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POWERSAVE_BIAS_DEF);
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return 0;
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}
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late_initcall(amd_freq_sensitivity_init);
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static void __exit amd_freq_sensitivity_exit(void)
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{
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od_unregister_powersave_bias_handler();
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}
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module_exit(amd_freq_sensitivity_exit);
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static const struct x86_cpu_id amd_freq_sensitivity_ids[] = {
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X86_FEATURE_MATCH(X86_FEATURE_PROC_FEEDBACK),
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{}
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};
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MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
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MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
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MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
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"the ondemand governor.");
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MODULE_LICENSE("GPL");
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