aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/platforms/cell/Kconfig9
-rw-r--r--arch/powerpc/platforms/cell/Makefile1
-rw-r--r--arch/powerpc/platforms/cell/cpufreq_spudemand.c184
3 files changed, 194 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/Kconfig b/arch/powerpc/platforms/cell/Kconfig
index 3959fcfe731..6ee571f743c 100644
--- a/arch/powerpc/platforms/cell/Kconfig
+++ b/arch/powerpc/platforms/cell/Kconfig
@@ -107,6 +107,15 @@ config CBE_CPUFREQ_PMI
processor will not only be able to run at lower speed,
but also at lower core voltage.
+config CBE_CPUFREQ_SPU_GOVERNOR
+ tristate "CBE frequency scaling based on SPU usage"
+ depends on SPU_FS && CPU_FREQ
+ default m
+ help
+ This governor checks for spu usage to adjust the cpu frequency.
+ If no spu is running on a given cpu, that cpu will be throttled to
+ the minimal possible frequency.
+
endmenu
config OPROFILE_CELL
diff --git a/arch/powerpc/platforms/cell/Makefile b/arch/powerpc/platforms/cell/Makefile
index c2a7e4e5ddf..7fcf09bd80b 100644
--- a/arch/powerpc/platforms/cell/Makefile
+++ b/arch/powerpc/platforms/cell/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_CBE_THERM) += cbe_thermal.o
obj-$(CONFIG_CBE_CPUFREQ_PMI) += cbe_cpufreq_pmi.o
obj-$(CONFIG_CBE_CPUFREQ) += cbe-cpufreq.o
cbe-cpufreq-y += cbe_cpufreq_pervasive.o cbe_cpufreq.o
+obj-$(CONFIG_CBE_CPUFREQ_SPU_GOVERNOR) += cpufreq_spudemand.o
ifeq ($(CONFIG_SMP),y)
obj-$(CONFIG_PPC_CELL_NATIVE) += smp.o
diff --git a/arch/powerpc/platforms/cell/cpufreq_spudemand.c b/arch/powerpc/platforms/cell/cpufreq_spudemand.c
new file mode 100644
index 00000000000..a3c6c01bd6d
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cpufreq_spudemand.c
@@ -0,0 +1,184 @@
+/*
+ * spu aware cpufreq governor for the cell processor
+ *
+ * © Copyright IBM Corporation 2006-2008
+ *
+ * Author: Christian Krafft <krafft@de.ibm.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; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <asm/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 struct workqueue_struct *kspugov_wq;
+
+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);
+
+ 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);
+ queue_delayed_work_on(info->policy->cpu, kspugov_wq, &info->work, delay);
+}
+
+static void spu_gov_init_work(struct spu_gov_info_struct *info)
+{
+ int delay = usecs_to_jiffies(info->poll_int);
+ INIT_DELAYED_WORK_DEFERRABLE(&info->work, spu_gov_work);
+ queue_delayed_work_on(info->policy->cpu, kspugov_wq, &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_govern(struct cpufreq_policy *policy, unsigned int event)
+{
+ unsigned int cpu = policy->cpu;
+ struct spu_gov_info_struct *info, *affected_info;
+ int i;
+ int ret = 0;
+
+ info = &per_cpu(spu_gov_info, cpu);
+
+ switch (event) {
+ case CPUFREQ_GOV_START:
+ if (!cpu_online(cpu)) {
+ printk(KERN_ERR "cpu %d is not online\n", cpu);
+ ret = -EINVAL;
+ break;
+ }
+
+ if (!policy->cur) {
+ printk(KERN_ERR "no cpu specified in policy\n");
+ ret = -EINVAL;
+ break;
+ }
+
+ /* initialize spu_gov_info for all affected cpus */
+ for_each_cpu_mask(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);
+
+ break;
+
+ case CPUFREQ_GOV_STOP:
+ /* cancel timer */
+ spu_gov_cancel_work(info);
+
+ /* clean spu_gov_info for all affected cpus */
+ for_each_cpu_mask (i, policy->cpus) {
+ info = &per_cpu(spu_gov_info, i);
+ info->policy = NULL;
+ }
+
+ break;
+ }
+
+ return ret;
+}
+
+static struct cpufreq_governor spu_governor = {
+ .name = "spudemand",
+ .governor = spu_gov_govern,
+ .owner = THIS_MODULE,
+};
+
+/*
+ * module init and destoy
+ */
+
+static int __init spu_gov_init(void)
+{
+ int ret;
+
+ kspugov_wq = create_workqueue("kspugov");
+ if (!kspugov_wq) {
+ printk(KERN_ERR "creation of kspugov failed\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = cpufreq_register_governor(&spu_governor);
+ if (ret) {
+ printk(KERN_ERR "registration of governor failed\n");
+ destroy_workqueue(kspugov_wq);
+ goto out;
+ }
+out:
+ return ret;
+}
+
+static void __exit spu_gov_exit(void)
+{
+ cpufreq_unregister_governor(&spu_governor);
+ destroy_workqueue(kspugov_wq);
+}
+
+
+module_init(spu_gov_init);
+module_exit(spu_gov_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-20 09:56:24 +0000