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: Martin Schwidefsky <schwidefsky@de.ibm.com>
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@ -8,6 +8,7 @@
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#define _S390_CPUTIME_H
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#include <linux/types.h>
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#include <asm/timex.h>
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#define CPUTIME_PER_USEC 4096ULL
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#define CPUTIME_PER_SEC (CPUTIME_PER_USEC * USEC_PER_SEC)
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#define cmpxchg_cputime(ptr, old, new) cmpxchg64(ptr, old, new)
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/*
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* Convert cputime to microseconds and back.
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* Convert cputime to microseconds.
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*/
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static inline u64 cputime_to_usecs(const u64 cputime)
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{
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return cputime >> 12;
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}
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/*
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* Convert cputime to nanoseconds.
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*/
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#define cputime_to_nsecs(cputime) tod_to_ns(cputime)
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u64 arch_cpu_idle_time(int cpu);
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#define arch_idle_time(cpu) arch_cpu_idle_time(cpu)
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