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Commit e53051e7 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/cputime: provide archicture specific cputime_to_nsecs 



The generic cputime_to_nsecs function first converts the cputime
to micro-seconds and then multiplies the result with 1000. This
looses some bits of accuracy, provide our own version of
cputime_to_nsecs that does not loose precision.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 3c915bdc

arch/s390/include/asm/cputime.h

+7 −1
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#define _S390_CPUTIME_H



#include <linux/types.h>

#include <asm/timex.h>



#define CPUTIME_PER_USEC 4096ULL

#define CPUTIME_PER_SEC (CPUTIME_PER_USEC * USEC_PER_SEC)
@@ -17,13 +18,18 @@ 
#define cmpxchg_cputime(ptr, old, new) cmpxchg64(ptr, old, new)



/*

 * Convert cputime to microseconds and back.

 * Convert cputime to microseconds.

 */

static inline u64 cputime_to_usecs(const u64 cputime)

{

	return cputime >> 12;

}



/*

 * Convert cputime to nanoseconds.

 */

#define cputime_to_nsecs(cputime) tod_to_ns(cputime)



u64 arch_cpu_idle_time(int cpu);



#define arch_idle_time(cpu) arch_cpu_idle_time(cpu)