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This newly introduced flag can be applied by a governor to a CPUFreq relation, when looking for a frequency within the policy table. The resolution would then only walk through efficient frequencies. Even with the flag set, the policy max limit will still be honoured. If no efficient frequencies can be found within the limits of the policy, an inefficient one would be returned. Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
157 lines
4 KiB
C
157 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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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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#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/pci.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 <asm/cpu_device_id.h>
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#include "cpufreq_ondemand.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 policy_dbs_info *policy_dbs = policy->governor_data;
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struct dbs_data *od_data = policy_dbs->dbs_data;
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struct od_dbs_tuners *od_tuners = od_data->tuners;
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if (!policy->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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index = cpufreq_table_find_index_h(policy,
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policy->cur - 1,
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relation & CPUFREQ_RELATION_E);
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freq_next = policy->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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struct pci_dev *pcidev;
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unsigned int pci_vendor;
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if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
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pci_vendor = PCI_VENDOR_ID_AMD;
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else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
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pci_vendor = PCI_VENDOR_ID_HYGON;
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else
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return -ENODEV;
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pcidev = pci_get_device(pci_vendor,
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PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
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if (!pcidev) {
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if (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK))
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return -ENODEV;
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}
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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 __maybe_unused amd_freq_sensitivity_ids[] = {
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X86_MATCH_FEATURE(X86_FEATURE_PROC_FEEDBACK, NULL),
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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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