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[S390] Add per-cpu idle time / idle count sysfs attributes.

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Add two new sysfs entries per cpu: idle_count and idle_time.
idle_count contains the number of times a cpu went into idle state.
idle_time contains the time a cpu spent in idle state in microseconds.
This can be used e.g. by powertop to tell how often idle state is
entered and left.

# cat /sys/devices/system/cpu/cpu0/idle_count
504
# cat /sys/devices/system/cpu/cpu0/idle_time
469734037 us

Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2007-10-22 12:52:39 +02:00 • committed by Martin Schwidefsky
commit fae8b22d3e
3 changed files with 101 additions and 3 deletions
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63
arch/s390/kernel/smp.c
View file

@ -42,6 +42,7 @@
#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/lowcore.h>
#include <asm/cpu.h>
/*
* An array with a pointer the lowcore of every CPU.
@ -494,6 +495,8 @@ int __cpuinit start_secondary(void *cpuvoid)
return 0;
}
DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
static void __init smp_create_idle(unsigned int cpu)
{
struct task_struct *p;
@ -506,6 +509,7 @@ static void __init smp_create_idle(unsigned int cpu)
if (IS_ERR(p))
panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
current_set[cpu] = p;
spin_lock_init(&(&per_cpu(s390_idle, cpu))->lock);
}
static int cpu_stopped(int cpu)
@ -724,6 +728,7 @@ void __init smp_prepare_boot_cpu(void)
cpu_set(0, cpu_online_map);
S390_lowcore.percpu_offset = __per_cpu_offset[0];
current_set[0] = current;
spin_lock_init(&(&__get_cpu_var(s390_idle))->lock);
}
void __init smp_cpus_done(unsigned int max_cpus)
@ -756,22 +761,71 @@ static ssize_t show_capability(struct sys_device *dev, char *buf)
}
static SYSDEV_ATTR(capability, 0444, show_capability, NULL);
static ssize_t show_idle_count(struct sys_device *dev, char *buf)
{
struct s390_idle_data *idle;
unsigned long long idle_count;
idle = &per_cpu(s390_idle, dev->id);
spin_lock_irq(&idle->lock);
idle_count = idle->idle_count;
spin_unlock_irq(&idle->lock);
return sprintf(buf, "%llu\n", idle_count);
}
static SYSDEV_ATTR(idle_count, 0444, show_idle_count, NULL);
static ssize_t show_idle_time(struct sys_device *dev, char *buf)
{
struct s390_idle_data *idle;
unsigned long long new_time;
idle = &per_cpu(s390_idle, dev->id);
spin_lock_irq(&idle->lock);
if (idle->in_idle) {
new_time = get_clock();
idle->idle_time += new_time - idle->idle_enter;
idle->idle_enter = new_time;
}
new_time = idle->idle_time;
spin_unlock_irq(&idle->lock);
return sprintf(buf, "%llu us\n", new_time >> 12);
}
static SYSDEV_ATTR(idle_time, 0444, show_idle_time, NULL);
static struct attribute *cpu_attrs[] = {
&attr_capability.attr,
&attr_idle_count.attr,
&attr_idle_time.attr,
NULL,
};
static struct attribute_group cpu_attr_group = {
.attrs = cpu_attrs,
};
static int __cpuinit smp_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned int)(long)hcpu;
struct cpu *c = &per_cpu(cpu_devices, cpu);
struct sys_device *s = &c->sysdev;
struct s390_idle_data *idle;
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
if (sysdev_create_file(s, &attr_capability))
idle = &per_cpu(s390_idle, cpu);
spin_lock_irq(&idle->lock);
idle->idle_enter = 0;
idle->idle_time = 0;
idle->idle_count = 0;
spin_unlock_irq(&idle->lock);
if (sysfs_create_group(&s->kobj, &cpu_attr_group))
return NOTIFY_BAD;
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
sysdev_remove_file(s, &attr_capability);
sysfs_remove_group(&s->kobj, &cpu_attr_group);
break;
}
return NOTIFY_OK;
@ -784,6 +838,7 @@ static struct notifier_block __cpuinitdata smp_cpu_nb = {
static int __init topology_init(void)
{
int cpu;
int rc;
register_cpu_notifier(&smp_cpu_nb);
@ -796,7 +851,9 @@ static int __init topology_init(void)
if (!cpu_online(cpu))
continue;
s = &c->sysdev;
sysdev_create_file(s, &attr_capability);
rc = sysfs_create_group(&s->kobj, &cpu_attr_group);
if (rc)
return rc;
}
return 0;
}