1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
* for the ondemand governor.
*
* Copyright (C) 2013 Advanced Micro Devices, Inc.
*
* Author: Jacob Shin <jacob.shin@amd.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/percpu-defs.h>
#include <linux/init.h>
#include <linux/mod_devicetable.h>
#include <asm/msr.h>
#include <asm/cpufeature.h>
#include <asm/cpu_device_id.h>
#include "cpufreq_ondemand.h"
#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL 0xc0010080
#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE 0xc0010081
#define CLASS_CODE_SHIFT 56
#define POWERSAVE_BIAS_MAX 1000
#define POWERSAVE_BIAS_DEF 400
struct cpu_data_t {
u64 actual;
u64 reference;
unsigned int freq_prev;
};
static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);
static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
unsigned int freq_next,
unsigned int relation)
{
int sensitivity;
long d_actual, d_reference;
struct msr actual, reference;
struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
struct policy_dbs_info *policy_dbs = policy->governor_data;
struct dbs_data *od_data = policy_dbs->dbs_data;
struct od_dbs_tuners *od_tuners = od_data->tuners;
if (!policy->freq_table)
return freq_next;
rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
&actual.l, &actual.h);
rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
&reference.l, &reference.h);
actual.h &= 0x00ffffff;
reference.h &= 0x00ffffff;
/* counter wrapped around, so stay on current frequency */
if (actual.q < data->actual || reference.q < data->reference) {
freq_next = policy->cur;
goto out;
}
d_actual = actual.q - data->actual;
d_reference = reference.q - data->reference;
/* divide by 0, so stay on current frequency as well */
if (d_reference == 0) {
freq_next = policy->cur;
goto out;
}
sensitivity = POWERSAVE_BIAS_MAX -
(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
/* this workload is not CPU bound, so choose a lower freq */
if (sensitivity < od_tuners->powersave_bias) {
if (data->freq_prev == policy->cur)
freq_next = policy->cur;
if (freq_next > policy->cur)
freq_next = policy->cur;
else if (freq_next < policy->cur)
freq_next = policy->min;
else {
unsigned int index;
index = cpufreq_table_find_index_h(policy,
policy->cur - 1);
freq_next = policy->freq_table[index].frequency;
}
data->freq_prev = freq_next;
} else
data->freq_prev = 0;
out:
data->actual = actual.q;
data->reference = reference.q;
return freq_next;
}
static int __init amd_freq_sensitivity_init(void)
{
u64 val;
struct pci_dev *pcidev;
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
return -ENODEV;
pcidev = pci_get_device(PCI_VENDOR_ID_AMD,
PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
if (!pcidev) {
if (!static_cpu_has(X86_FEATURE_PROC_FEEDBACK))
return -ENODEV;
}
if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
return -ENODEV;
if (!(val >> CLASS_CODE_SHIFT))
return -ENODEV;
od_register_powersave_bias_handler(amd_powersave_bias_target,
POWERSAVE_BIAS_DEF);
return 0;
}
late_initcall(amd_freq_sensitivity_init);
static void __exit amd_freq_sensitivity_exit(void)
{
od_unregister_powersave_bias_handler();
}
module_exit(amd_freq_sensitivity_exit);
static const struct x86_cpu_id amd_freq_sensitivity_ids[] = {
X86_FEATURE_MATCH(X86_FEATURE_PROC_FEEDBACK),
{}
};
MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
"the ondemand governor.");
MODULE_LICENSE("GPL");
|
