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Commit fae8b22d authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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[S390] Add per-cpu idle time / idle count sysfs attributes. 



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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 32346f47

arch/s390/kernel/process.c

+16 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include <asm/processor.h>

#include <asm/irq.h>

#include <asm/timer.h>

#include <asm/cpu.h>



asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
@@ -91,6 +92,14 @@ EXPORT_SYMBOL(unregister_idle_notifier); 


void do_monitor_call(struct pt_regs *regs, long interruption_code)

{

	struct s390_idle_data *idle;



	idle = &__get_cpu_var(s390_idle);

	spin_lock(&idle->lock);

	idle->idle_time += get_clock() - idle->idle_enter;

	idle->in_idle = 0;

	spin_unlock(&idle->lock);



	/* disable monitor call class 0 */

	__ctl_clear_bit(8, 15);
@@ -105,6 +114,7 @@ extern void s390_handle_mcck(void); 
static void default_idle(void)

{

	int cpu, rc;

	struct s390_idle_data *idle;



	/* CPU is going idle. */

	cpu = smp_processor_id();
@@ -142,6 +152,12 @@ static void default_idle(void) 
		return;

	}



	idle = &__get_cpu_var(s390_idle);

	spin_lock(&idle->lock);

	idle->idle_count++;

	idle->in_idle = 1;

	idle->idle_enter = get_clock();

	spin_unlock(&idle->lock);

	trace_hardirqs_on();

	/* Wait for external, I/O or machine check interrupt. */

	__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |

arch/s390/kernel/smp.c

+60 −3
Original line number Diff line number Diff line
@@ -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;

}

include/asm-s390/cpu.h

0 → 100644
+25 −0
Original line number Diff line number Diff line 
/*

 *  include/asm-s390/cpu.h

 *

 *    Copyright IBM Corp. 2007

 *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>

 */



#ifndef _ASM_S390_CPU_H_

#define _ASM_S390_CPU_H_



#include <linux/types.h>

#include <linux/percpu.h>

#include <linux/spinlock.h>



struct s390_idle_data {

	spinlock_t lock;

	unsigned int in_idle;

	unsigned long long idle_count;

	unsigned long long idle_enter;

	unsigned long long idle_time;

};



DECLARE_PER_CPU(struct s390_idle_data, s390_idle);



#endif /* _ASM_S390_CPU_H_ */