Commit e1c80530 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

[S390] /proc/stat idle field for idle cpus 



The cpu idle field in the output of /proc/stat is too small for cpus
that have been idle for more than a tick. Add the architecture hook
arch_idle_time that allows to add the not accounted idle time of a
sleeping cpu without waking the cpu.

The s390 implementation of arch_idle_time uses the already existing
s390_idle_data per_cpu variable to find the sleep time of a neighboring
idle cpu.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent b1ad171e

arch/s390/include/asm/cputime.h

+4 −0
Original line number Diff line number Diff line
@@ -174,4 +174,8 @@ cputime64_to_clock_t(cputime64_t cputime) 
       return __div(cputime, 4096000000ULL / USER_HZ);

}



cputime64_t s390_get_idle_time(int cpu);



#define arch_idle_time(cpu) s390_get_idle_time(cpu)



#endif /* _S390_CPUTIME_H */

arch/s390/kernel/vtime.c

+16 −0
Original line number Diff line number Diff line
@@ -240,6 +240,22 @@ void vtime_stop_cpu(void) 
	}

}



cputime64_t s390_get_idle_time(int cpu)

{

	struct s390_idle_data *idle;

	unsigned long long now, idle_time, idle_enter;



	idle = &per_cpu(s390_idle, cpu);

	spin_lock(&idle->lock);

	now = get_clock();

	idle_time = 0;

	idle_enter = idle->idle_enter;

	if (idle_enter != 0ULL && idle_enter < now)

		idle_time = now - idle_enter;

	spin_unlock(&idle->lock);

	return idle_time;

}



/*

 * Sorted add to a list. List is linear searched until first bigger

 * element is found.

fs/proc/stat.c

+5 −0
Original line number Diff line number Diff line
@@ -18,6 +18,9 @@ 
#ifndef arch_irq_stat

#define arch_irq_stat() 0

#endif

#ifndef arch_idle_time

#define arch_idle_time(cpu) 0

#endif



static int show_stat(struct seq_file *p, void *v)

{
@@ -40,6 +43,7 @@ static int show_stat(struct seq_file *p, void *v) 
		nice = cputime64_add(nice, kstat_cpu(i).cpustat.nice);

		system = cputime64_add(system, kstat_cpu(i).cpustat.system);

		idle = cputime64_add(idle, kstat_cpu(i).cpustat.idle);

		idle = cputime64_add(idle, arch_idle_time(i));

		iowait = cputime64_add(iowait, kstat_cpu(i).cpustat.iowait);

		irq = cputime64_add(irq, kstat_cpu(i).cpustat.irq);

		softirq = cputime64_add(softirq, kstat_cpu(i).cpustat.softirq);
@@ -69,6 +73,7 @@ static int show_stat(struct seq_file *p, void *v) 
		nice = kstat_cpu(i).cpustat.nice;

		system = kstat_cpu(i).cpustat.system;

		idle = kstat_cpu(i).cpustat.idle;

		idle = cputime64_add(idle, arch_idle_time(i));

		iowait = kstat_cpu(i).cpustat.iowait;

		irq = kstat_cpu(i).cpustat.irq;

		softirq = kstat_cpu(i).cpustat.softirq;

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