On Fri, 2008-07-04 at 21:05 +0200, [EMAIL PROTECTED] wrote:
> plain text document attachment
> (0005-powerpc-cell-add-spu-aware-cpufreq-governor.patch)
> This patch adds a cpufreq governor that takes the number of running spus
> into account. It's very similar to the ondemand governor, but not as complex.
> Instead of hacking spu load into the ondemand governor it might be easier to
> have cpufreq accepting multiple governors per cpu in future.
> Don't know if this is the right way, but it would keep the governors simple.
>
> Signed-off-by: Christian Krafft <[EMAIL PROTECTED]>
Arnd, your S-O-B ?
Also, there's the question of whether this should also go in
drivers/cpufreq or not and should be reviewed by the cpufreq
maintainer (whoever that is), no ?
Cheers,
Ben.
> ---
> arch/powerpc/platforms/cell/Kconfig | 10 ++
> arch/powerpc/platforms/cell/Makefile | 1 +
> arch/powerpc/platforms/cell/cbe_spu_governor.c | 183
> ++++++++++++++++++++++++
> 3 files changed, 194 insertions(+), 0 deletions(-)
> create mode 100644 arch/powerpc/platforms/cell/cbe_spu_governor.c
>
> diff --git a/arch/powerpc/platforms/cell/Kconfig
> b/arch/powerpc/platforms/cell/Kconfig
> index 3959fcf..2dfff9f 100644
> --- a/arch/powerpc/platforms/cell/Kconfig
> +++ b/arch/powerpc/platforms/cell/Kconfig
> @@ -107,6 +107,16 @@ 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
> + select CBE_CPUFREQ
> + 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 c2a7e4e..8be5158 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) += cbe_spu_governor.o
>
> ifeq ($(CONFIG_SMP),y)
> obj-$(CONFIG_PPC_CELL_NATIVE) += smp.o
> diff --git a/arch/powerpc/platforms/cell/cbe_spu_governor.c
> b/arch/powerpc/platforms/cell/cbe_spu_governor.c
> new file mode 100644
> index 0000000..7e63009
> --- /dev/null
> +++ b/arch/powerpc/platforms/cell/cbe_spu_governor.c
> @@ -0,0 +1,183 @@
> +/*
> + * spu aware cpufreq governor for the cell processor
> + *
> + * (C) Copyright IBM Corporation 2006-2008
> + *
> + * Author: Christian Krafft <[EMAIL PROTECTED]>
> + *
> + * 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 us */
> +#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; /* us */
> +};
> +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(KERN_ERR "cpu %d: busy_spus=%d, info->busy_spus=%d\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 = "spu_governor",
> + .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 <[EMAIL PROTECTED]>");
> +
> --
> 1.5.4.3
>
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