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

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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: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2009-04-23 13:58:08 +02:00
parent b1ad171efa
commit e1c805309d
3 changed files with 25 additions and 0 deletions
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4
arch/s390/include/asm/cputime.h
View file

@ -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 */

16
arch/s390/kernel/vtime.c
View file

@ -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.

5
fs/proc/stat.c
View file

@ -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;