linux/arch/s390/include/asm/cputime.h
Martin Schwidefsky aa5e97ce4b [PATCH] improve precision of process accounting.
The unit of the cputime accouting values that are stored per process is
currently a microsecond. The CPU timer has a maximum granularity of
2**-12 microseconds. There is no benefit in storing the per process values
in the lesser precision and there is the disadvantage that the backend
has to do the rounding to microseconds. The better solution is to use
the maximum granularity of the CPU timer as cputime unit.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 15:11:47 +01:00

177 lines
3.9 KiB
C

/*
* include/asm-s390/cputime.h
*
* (C) Copyright IBM Corp. 2004
*
* Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#ifndef _S390_CPUTIME_H
#define _S390_CPUTIME_H
#include <asm/div64.h>
/* We want to use full resolution of the CPU timer: 2**-12 micro-seconds. */
typedef unsigned long long cputime_t;
typedef unsigned long long cputime64_t;
#ifndef __s390x__
static inline unsigned int
__div(unsigned long long n, unsigned int base)
{
register_pair rp;
rp.pair = n >> 1;
asm ("dr %0,%1" : "+d" (rp) : "d" (base >> 1));
return rp.subreg.odd;
}
#else /* __s390x__ */
static inline unsigned int
__div(unsigned long long n, unsigned int base)
{
return n / base;
}
#endif /* __s390x__ */
#define cputime_zero (0ULL)
#define cputime_max ((~0UL >> 1) - 1)
#define cputime_add(__a, __b) ((__a) + (__b))
#define cputime_sub(__a, __b) ((__a) - (__b))
#define cputime_div(__a, __n) ({ \
unsigned long long __div = (__a); \
do_div(__div,__n); \
__div; \
})
#define cputime_halve(__a) ((__a) >> 1)
#define cputime_eq(__a, __b) ((__a) == (__b))
#define cputime_gt(__a, __b) ((__a) > (__b))
#define cputime_ge(__a, __b) ((__a) >= (__b))
#define cputime_lt(__a, __b) ((__a) < (__b))
#define cputime_le(__a, __b) ((__a) <= (__b))
#define cputime_to_jiffies(__ct) (__div((__ct), 4096000000ULL / HZ))
#define cputime_to_scaled(__ct) (__ct)
#define jiffies_to_cputime(__hz) ((cputime_t)(__hz) * (4096000000ULL / HZ))
#define cputime64_zero (0ULL)
#define cputime64_add(__a, __b) ((__a) + (__b))
#define cputime_to_cputime64(__ct) (__ct)
static inline u64
cputime64_to_jiffies64(cputime64_t cputime)
{
do_div(cputime, 4096000000ULL / HZ);
return cputime;
}
/*
* Convert cputime to milliseconds and back.
*/
static inline unsigned int
cputime_to_msecs(const cputime_t cputime)
{
return __div(cputime, 4096000);
}
static inline cputime_t
msecs_to_cputime(const unsigned int m)
{
return (cputime_t) m * 4096000;
}
/*
* Convert cputime to milliseconds and back.
*/
static inline unsigned int
cputime_to_secs(const cputime_t cputime)
{
return __div(cputime, 2048000000) >> 1;
}
static inline cputime_t
secs_to_cputime(const unsigned int s)
{
return (cputime_t) s * 4096000000ULL;
}
/*
* Convert cputime to timespec and back.
*/
static inline cputime_t
timespec_to_cputime(const struct timespec *value)
{
return value->tv_nsec * 4096 / 1000 + (u64) value->tv_sec * 4096000000ULL;
}
static inline void
cputime_to_timespec(const cputime_t cputime, struct timespec *value)
{
#ifndef __s390x__
register_pair rp;
rp.pair = cputime >> 1;
asm ("dr %0,%1" : "+d" (rp) : "d" (2048000000UL));
value->tv_nsec = rp.subreg.even * 1000 / 4096;
value->tv_sec = rp.subreg.odd;
#else
value->tv_nsec = (cputime % 4096000000ULL) * 1000 / 4096;
value->tv_sec = cputime / 4096000000ULL;
#endif
}
/*
* Convert cputime to timeval and back.
* Since cputime and timeval have the same resolution (microseconds)
* this is easy.
*/
static inline cputime_t
timeval_to_cputime(const struct timeval *value)
{
return value->tv_usec * 4096 + (u64) value->tv_sec * 4096000000ULL;
}
static inline void
cputime_to_timeval(const cputime_t cputime, struct timeval *value)
{
#ifndef __s390x__
register_pair rp;
rp.pair = cputime >> 1;
asm ("dr %0,%1" : "+d" (rp) : "d" (2048000000UL));
value->tv_usec = rp.subreg.even / 4096;
value->tv_sec = rp.subreg.odd;
#else
value->tv_usec = cputime % 4096000000ULL;
value->tv_sec = cputime / 4096000000ULL;
#endif
}
/*
* Convert cputime to clock and back.
*/
static inline clock_t
cputime_to_clock_t(cputime_t cputime)
{
return __div(cputime, 4096000000ULL / USER_HZ);
}
static inline cputime_t
clock_t_to_cputime(unsigned long x)
{
return (cputime_t) x * (4096000000ULL / USER_HZ);
}
/*
* Convert cputime64 to clock.
*/
static inline clock_t
cputime64_to_clock_t(cputime64_t cputime)
{
return __div(cputime, 4096000000ULL / USER_HZ);
}
#endif /* _S390_CPUTIME_H */