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#ifndef _ASMi386_TIMER_H
#define _ASMi386_TIMER_H
#include <linux/init.h>
#include <linux/pm.h>
#define TICK_SIZE (tick_nsec / 1000)
unsigned long long native_sched_clock(void);
unsigned long native_calculate_cpu_khz(void);
extern int timer_ack;
extern int no_timer_check;
extern int recalibrate_cpu_khz(void);
#ifndef CONFIG_PARAVIRT
#define calculate_cpu_khz() native_calculate_cpu_khz()
#endif
/* Accellerators for sched_clock()
* convert from cycles(64bits) => nanoseconds (64bits)
* basic equation:
* ns = cycles / (freq / ns_per_sec)
* ns = cycles * (ns_per_sec / freq)
* ns = cycles * (10^9 / (cpu_khz * 10^3))
* ns = cycles * (10^6 / cpu_khz)
*
* Then we use scaling math (suggested by george@mvista.com) to get:
* ns = cycles * (10^6 * SC / cpu_khz) / SC
* ns = cycles * cyc2ns_scale / SC
*
* And since SC is a constant power of two, we can convert the div
* into a shift.
*
* We can use khz divisor instead of mhz to keep a better percision, since
* cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
* (mathieu.desnoyers@polymtl.ca)
*
* -johnstul@us.ibm.com "math is hard, lets go shopping!"
*/
extern unsigned long cyc2ns_scale __read_mostly;
#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
static inline unsigned long long cycles_2_ns(unsigned long long cyc)
{
return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
}
#endif
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