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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 | // SPDX-License-Identifier: GPL-2.0-or-later /* * spu aware cpufreq governor for the cell processor * * © Copyright IBM Corporation 2006-2008 * * Author: Christian Krafft <krafft@de.ibm.com> */ #include <linux/cpufreq.h> #include <linux/sched.h> #include <linux/sched/loadavg.h> #include <linux/module.h> #include <linux/timer.h> #include <linux/workqueue.h> #include <linux/atomic.h> #include <asm/machdep.h> #include <asm/spu.h> #define POLL_TIME 100000 /* in µs */ #define EXP 753 /* exp(-1) in fixed-point */ struct spu_gov_info_struct { unsigned long busy_spus; /* fixed-point */ struct cpufreq_policy *policy; struct delayed_work work; unsigned int poll_int; /* µs */ }; static DEFINE_PER_CPU(struct spu_gov_info_struct, spu_gov_info); static int calc_freq(struct spu_gov_info_struct *info) { int cpu; int busy_spus; cpu = info->policy->cpu; busy_spus = atomic_read(&cbe_spu_info[cpu_to_node(cpu)].busy_spus); info->busy_spus = calc_load(info->busy_spus, EXP, busy_spus * FIXED_1); pr_debug("cpu %d: busy_spus=%d, info->busy_spus=%ld\n", cpu, busy_spus, info->busy_spus); return info->policy->max * info->busy_spus / FIXED_1; } static void spu_gov_work(struct work_struct *work) { struct spu_gov_info_struct *info; int delay; unsigned long target_freq; info = container_of(work, struct spu_gov_info_struct, work.work); /* after cancel_delayed_work_sync we unset info->policy */ BUG_ON(info->policy == NULL); target_freq = calc_freq(info); __cpufreq_driver_target(info->policy, target_freq, CPUFREQ_RELATION_H); delay = usecs_to_jiffies(info->poll_int); schedule_delayed_work_on(info->policy->cpu, &info->work, delay); } static void spu_gov_init_work(struct spu_gov_info_struct *info) { int delay = usecs_to_jiffies(info->poll_int); INIT_DEFERRABLE_WORK(&info->work, spu_gov_work); schedule_delayed_work_on(info->policy->cpu, &info->work, delay); } static void spu_gov_cancel_work(struct spu_gov_info_struct *info) { cancel_delayed_work_sync(&info->work); } static int spu_gov_start(struct cpufreq_policy *policy) { unsigned int cpu = policy->cpu; struct spu_gov_info_struct *info = &per_cpu(spu_gov_info, cpu); struct spu_gov_info_struct *affected_info; int i; if (!cpu_online(cpu)) { printk(KERN_ERR "cpu %d is not online\n", cpu); return -EINVAL; } if (!policy->cur) { printk(KERN_ERR "no cpu specified in policy\n"); return -EINVAL; } /* initialize spu_gov_info for all affected cpus */ for_each_cpu(i, policy->cpus) { affected_info = &per_cpu(spu_gov_info, i); affected_info->policy = policy; } info->poll_int = POLL_TIME; /* setup timer */ spu_gov_init_work(info); return 0; } static void spu_gov_stop(struct cpufreq_policy *policy) { unsigned int cpu = policy->cpu; struct spu_gov_info_struct *info = &per_cpu(spu_gov_info, cpu); int i; /* cancel timer */ spu_gov_cancel_work(info); /* clean spu_gov_info for all affected cpus */ for_each_cpu (i, policy->cpus) { info = &per_cpu(spu_gov_info, i); info->policy = NULL; } } static struct cpufreq_governor spu_governor = { .name = "spudemand", .start = spu_gov_start, .stop = spu_gov_stop, .owner = THIS_MODULE, }; cpufreq_governor_init(spu_governor); cpufreq_governor_exit(spu_governor); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); |