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linux/arch/powerpc/kernel/sysfs.c
Anton Blanchard 0ddd3e7d07 [POWERPC] Always call cede in pseries dedicated idle loop 
The smt_snooze_delay logic changed a bit when the idle loops were
consolidated. A value of 0 used to mean we always polled, now it means
we always sleep. Instead of restoring the old behaviour, lets put a
reasonable default in smt_snooze_delay. This means we spin for a bit
(in case an external interrupt comes in) and then sleep.

Also the pseries dedicated idle loop currently does not cede both
threads in an SMT pair. The hypervisor wants us to call in so it can
power manage, so lets do that.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-09-26 15:24:34 +10:00

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#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/nodemask.h>
#include <linux/cpumask.h>
#include <linux/notifier.h>
#include <asm/current.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
#include <asm/hvcall.h>
#include <asm/prom.h>
#include <asm/paca.h>
#include <asm/lppaca.h>
#include <asm/machdep.h>
#include <asm/smp.h>
static DEFINE_PER_CPU(struct cpu, cpu_devices);
/* SMT stuff */
#ifdef CONFIG_PPC_MULTIPLATFORM
/* Time in microseconds we delay before sleeping in the idle loop */
DEFINE_PER_CPU(unsigned long, smt_snooze_delay) = { 100 };
static ssize_t store_smt_snooze_delay(struct sys_device *dev, const char *buf,
size_t count)
{
struct cpu *cpu = container_of(dev, struct cpu, sysdev);
ssize_t ret;
unsigned long snooze;
ret = sscanf(buf, "%lu", &snooze);
if (ret != 1)
return -EINVAL;
per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
return count;
}
static ssize_t show_smt_snooze_delay(struct sys_device *dev, char *buf)
{
struct cpu *cpu = container_of(dev, struct cpu, sysdev);
return sprintf(buf, "%lu\n", per_cpu(smt_snooze_delay, cpu->sysdev.id));
}
static SYSDEV_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
store_smt_snooze_delay);
/* Only parse OF options if the matching cmdline option was not specified */
static int smt_snooze_cmdline;
static int __init smt_setup(void)
{
struct device_node *options;
const unsigned int *val;
unsigned int cpu;
if (!cpu_has_feature(CPU_FTR_SMT))
return -ENODEV;
options = find_path_device("/options");
if (!options)
return -ENODEV;
val = get_property(options, "ibm,smt-snooze-delay", NULL);
if (!smt_snooze_cmdline && val) {
for_each_possible_cpu(cpu)
per_cpu(smt_snooze_delay, cpu) = *val;
}
return 0;
}
__initcall(smt_setup);
static int __init setup_smt_snooze_delay(char *str)
{
unsigned int cpu;
int snooze;
if (!cpu_has_feature(CPU_FTR_SMT))
return 1;
smt_snooze_cmdline = 1;
if (get_option(&str, &snooze)) {
for_each_possible_cpu(cpu)
per_cpu(smt_snooze_delay, cpu) = snooze;
}
return 1;
}
__setup("smt-snooze-delay=", setup_smt_snooze_delay);
#endif /* CONFIG_PPC_MULTIPLATFORM */
/*
* Enabling PMCs will slow partition context switch times so we only do
* it the first time we write to the PMCs.
*/
static DEFINE_PER_CPU(char, pmcs_enabled);
void ppc64_enable_pmcs(void)
{
/* Only need to enable them once */
if (__get_cpu_var(pmcs_enabled))
return;
__get_cpu_var(pmcs_enabled) = 1;
if (ppc_md.enable_pmcs)
ppc_md.enable_pmcs();
}
EXPORT_SYMBOL(ppc64_enable_pmcs);
/* XXX convert to rusty's on_one_cpu */
static unsigned long run_on_cpu(unsigned long cpu,
unsigned long (*func)(unsigned long),
unsigned long arg)
{
cpumask_t old_affinity = current->cpus_allowed;
unsigned long ret;
/* should return -EINVAL to userspace */
if (set_cpus_allowed(current, cpumask_of_cpu(cpu)))
return 0;
ret = func(arg);
set_cpus_allowed(current, old_affinity);
return ret;
}
#define SYSFS_PMCSETUP(NAME, ADDRESS) \
static unsigned long read_##NAME(unsigned long junk) \
{ \
return mfspr(ADDRESS); \
} \
static unsigned long write_##NAME(unsigned long val) \
{ \
ppc64_enable_pmcs(); \
mtspr(ADDRESS, val); \
return 0; \
} \
static ssize_t show_##NAME(struct sys_device *dev, char *buf) \
{ \
struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
unsigned long val = run_on_cpu(cpu->sysdev.id, read_##NAME, 0); \
return sprintf(buf, "%lx\n", val); \
} \
static ssize_t __attribute_used__ \
store_##NAME(struct sys_device *dev, const char *buf, size_t count) \
{ \
struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
unsigned long val; \
int ret = sscanf(buf, "%lx", &val); \
if (ret != 1) \
return -EINVAL; \
run_on_cpu(cpu->sysdev.id, write_##NAME, val); \
return count; \
}
SYSFS_PMCSETUP(mmcr0, SPRN_MMCR0);
SYSFS_PMCSETUP(mmcr1, SPRN_MMCR1);
SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
SYSFS_PMCSETUP(pmc1, SPRN_PMC1);
SYSFS_PMCSETUP(pmc2, SPRN_PMC2);
SYSFS_PMCSETUP(pmc3, SPRN_PMC3);
SYSFS_PMCSETUP(pmc4, SPRN_PMC4);
SYSFS_PMCSETUP(pmc5, SPRN_PMC5);
SYSFS_PMCSETUP(pmc6, SPRN_PMC6);
SYSFS_PMCSETUP(pmc7, SPRN_PMC7);
SYSFS_PMCSETUP(pmc8, SPRN_PMC8);
SYSFS_PMCSETUP(purr, SPRN_PURR);
static SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0);
static SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1);
static SYSDEV_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
static SYSDEV_ATTR(pmc1, 0600, show_pmc1, store_pmc1);
static SYSDEV_ATTR(pmc2, 0600, show_pmc2, store_pmc2);
static SYSDEV_ATTR(pmc3, 0600, show_pmc3, store_pmc3);
static SYSDEV_ATTR(pmc4, 0600, show_pmc4, store_pmc4);
static SYSDEV_ATTR(pmc5, 0600, show_pmc5, store_pmc5);
static SYSDEV_ATTR(pmc6, 0600, show_pmc6, store_pmc6);
static SYSDEV_ATTR(pmc7, 0600, show_pmc7, store_pmc7);
static SYSDEV_ATTR(pmc8, 0600, show_pmc8, store_pmc8);
static SYSDEV_ATTR(purr, 0600, show_purr, NULL);
static void register_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct sys_device *s = &c->sysdev;
#ifndef CONFIG_PPC_ISERIES
if (cpu_has_feature(CPU_FTR_SMT))
sysdev_create_file(s, &attr_smt_snooze_delay);
#endif
/* PMC stuff */
sysdev_create_file(s, &attr_mmcr0);
sysdev_create_file(s, &attr_mmcr1);
if (cpu_has_feature(CPU_FTR_MMCRA))
sysdev_create_file(s, &attr_mmcra);
if (cur_cpu_spec->num_pmcs >= 1)
sysdev_create_file(s, &attr_pmc1);
if (cur_cpu_spec->num_pmcs >= 2)
sysdev_create_file(s, &attr_pmc2);
if (cur_cpu_spec->num_pmcs >= 3)
sysdev_create_file(s, &attr_pmc3);
if (cur_cpu_spec->num_pmcs >= 4)
sysdev_create_file(s, &attr_pmc4);
if (cur_cpu_spec->num_pmcs >= 5)
sysdev_create_file(s, &attr_pmc5);
if (cur_cpu_spec->num_pmcs >= 6)
sysdev_create_file(s, &attr_pmc6);
if (cur_cpu_spec->num_pmcs >= 7)
sysdev_create_file(s, &attr_pmc7);
if (cur_cpu_spec->num_pmcs >= 8)
sysdev_create_file(s, &attr_pmc8);
if (cpu_has_feature(CPU_FTR_PURR))
sysdev_create_file(s, &attr_purr);
}
#ifdef CONFIG_HOTPLUG_CPU
static void unregister_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct sys_device *s = &c->sysdev;
BUG_ON(c->no_control);
#ifndef CONFIG_PPC_ISERIES
if (cpu_has_feature(CPU_FTR_SMT))
sysdev_remove_file(s, &attr_smt_snooze_delay);
#endif
/* PMC stuff */
sysdev_remove_file(s, &attr_mmcr0);
sysdev_remove_file(s, &attr_mmcr1);
if (cpu_has_feature(CPU_FTR_MMCRA))
sysdev_remove_file(s, &attr_mmcra);
if (cur_cpu_spec->num_pmcs >= 1)
sysdev_remove_file(s, &attr_pmc1);
if (cur_cpu_spec->num_pmcs >= 2)
sysdev_remove_file(s, &attr_pmc2);
if (cur_cpu_spec->num_pmcs >= 3)
sysdev_remove_file(s, &attr_pmc3);
if (cur_cpu_spec->num_pmcs >= 4)
sysdev_remove_file(s, &attr_pmc4);
if (cur_cpu_spec->num_pmcs >= 5)
sysdev_remove_file(s, &attr_pmc5);
if (cur_cpu_spec->num_pmcs >= 6)
sysdev_remove_file(s, &attr_pmc6);
if (cur_cpu_spec->num_pmcs >= 7)
sysdev_remove_file(s, &attr_pmc7);
if (cur_cpu_spec->num_pmcs >= 8)
sysdev_remove_file(s, &attr_pmc8);
if (cpu_has_feature(CPU_FTR_PURR))
sysdev_remove_file(s, &attr_purr);
}
#endif /* CONFIG_HOTPLUG_CPU */
static int __cpuinit sysfs_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned int)(long)hcpu;
switch (action) {
case CPU_ONLINE:
register_cpu_online(cpu);
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD:
unregister_cpu_online(cpu);
break;
#endif
}
return NOTIFY_OK;
}
static struct notifier_block __cpuinitdata sysfs_cpu_nb = {
.notifier_call = sysfs_cpu_notify,
};
/* NUMA stuff */
#ifdef CONFIG_NUMA
static void register_nodes(void)
{
int i;
for (i = 0; i < MAX_NUMNODES; i++)
register_one_node(i);
}
int sysfs_add_device_to_node(struct sys_device *dev, int nid)
{
struct node *node = &node_devices[nid];
return sysfs_create_link(&node->sysdev.kobj, &dev->kobj,
kobject_name(&dev->kobj));
}
void sysfs_remove_device_from_node(struct sys_device *dev, int nid)
{
struct node *node = &node_devices[nid];
sysfs_remove_link(&node->sysdev.kobj, kobject_name(&dev->kobj));
}
#else
static void register_nodes(void)
{
return;
}
#endif
EXPORT_SYMBOL_GPL(sysfs_add_device_to_node);
EXPORT_SYMBOL_GPL(sysfs_remove_device_from_node);
/* Only valid if CPU is present. */
static ssize_t show_physical_id(struct sys_device *dev, char *buf)
{
struct cpu *cpu = container_of(dev, struct cpu, sysdev);
return sprintf(buf, "%d\n", get_hard_smp_processor_id(cpu->sysdev.id));
}
static SYSDEV_ATTR(physical_id, 0444, show_physical_id, NULL);
static int __init topology_init(void)
{
int cpu;
register_nodes();
register_cpu_notifier(&sysfs_cpu_nb);
for_each_possible_cpu(cpu) {
struct cpu *c = &per_cpu(cpu_devices, cpu);
/*
* For now, we just see if the system supports making
* the RTAS calls for CPU hotplug. But, there may be a
* more comprehensive way to do this for an individual
* CPU. For instance, the boot cpu might never be valid
* for hotplugging.
*/
if (!ppc_md.cpu_die)
c->no_control = 1;
if (cpu_online(cpu) || (c->no_control == 0)) {
register_cpu(c, cpu);
sysdev_create_file(&c->sysdev, &attr_physical_id);
}
if (cpu_online(cpu))
register_cpu_online(cpu);
}
return 0;
}
__initcall(topology_init);
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