blob: 63c9b3e3509d4703f8da44b6e6345e2cba01184c (
plain)
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
|
/*
* itmt.c: Support Intel Turbo Boost Max Technology 3.0
*
* (C) Copyright 2016 Intel Corporation
* Author: Tim Chen <tim.c.chen@linux.intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*
* On platforms supporting Intel Turbo Boost Max Technology 3.0, (ITMT),
* the maximum turbo frequencies of some cores in a CPU package may be
* higher than for the other cores in the same package. In that case,
* better performance can be achieved by making the scheduler prefer
* to run tasks on the CPUs with higher max turbo frequencies.
*
* This file provides functions and data structures for enabling the
* scheduler to favor scheduling on cores can be boosted to a higher
* frequency under ITMT.
*/
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/cpuset.h>
#include <asm/mutex.h>
#include <linux/sched.h>
#include <linux/sysctl.h>
#include <linux/nodemask.h>
static DEFINE_MUTEX(itmt_update_mutex);
DEFINE_PER_CPU_READ_MOSTLY(int, sched_core_priority);
/* Boolean to track if system has ITMT capabilities */
static bool __read_mostly sched_itmt_capable;
/**
* sched_set_itmt_support() - Indicate platform supports ITMT
*
* This function is used by the OS to indicate to scheduler that the platform
* is capable of supporting the ITMT feature.
*
* The current scheme has the pstate driver detects if the system
* is ITMT capable and call sched_set_itmt_support.
*
* This must be done only after sched_set_itmt_core_prio
* has been called to set the cpus' priorities.
*/
void sched_set_itmt_support(void)
{
mutex_lock(&itmt_update_mutex);
sched_itmt_capable = true;
mutex_unlock(&itmt_update_mutex);
}
/**
* sched_clear_itmt_support() - Revoke platform's support of ITMT
*
* This function is used by the OS to indicate that it has
* revoked the platform's support of ITMT feature.
*
*/
void sched_clear_itmt_support(void)
{
mutex_lock(&itmt_update_mutex);
sched_itmt_capable = false;
mutex_unlock(&itmt_update_mutex);
}
int arch_asym_cpu_priority(int cpu)
{
return per_cpu(sched_core_priority, cpu);
}
/**
* sched_set_itmt_core_prio() - Set CPU priority based on ITMT
* @prio: Priority of cpu core
* @core_cpu: The cpu number associated with the core
*
* The pstate driver will find out the max boost frequency
* and call this function to set a priority proportional
* to the max boost frequency. CPU with higher boost
* frequency will receive higher priority.
*
* No need to rebuild sched domain after updating
* the CPU priorities. The sched domains have no
* dependency on CPU priorities.
*/
void sched_set_itmt_core_prio(int prio, int core_cpu)
{
int cpu, i = 1;
for_each_cpu(cpu, topology_sibling_cpumask(core_cpu)) {
int smt_prio;
/*
* Ensure that the siblings are moved to the end
* of the priority chain and only used when
* all other high priority cpus are out of capacity.
*/
smt_prio = prio * smp_num_siblings / i;
per_cpu(sched_core_priority, cpu) = smt_prio;
i++;
}
}
|
