blob: 97b828ce31e0b8687d7bd04a6d5cbf278d6fc0dd [file] [log] [blame]
* linux/include/asm-i386/tsc.h
* i386 TSC related functions
#ifndef _ASM_i386_TSC_H
#define _ASM_i386_TSC_H
#include <linux/config.h>
#include <asm/processor.h>
* Standard way to access the cycle counter on i586+ CPUs.
* Currently only used on SMP.
* If you really have a SMP machine with i486 chips or older,
* compile for that, and this will just always return zero.
* That's ok, it just means that the nicer scheduling heuristics
* won't work for you.
* We only use the low 32 bits, and we'd simply better make sure
* that we reschedule before that wraps. Scheduling at least every
* four billion cycles just basically sounds like a good idea,
* regardless of how fast the machine is.
typedef unsigned long long cycles_t;
extern unsigned int cpu_khz;
extern unsigned int tsc_khz;
static inline cycles_t get_cycles(void)
unsigned long long ret = 0;
#ifndef CONFIG_X86_TSC
if (!cpu_has_tsc)
return 0;
#if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
return ret;
extern void tsc_init(void);
extern void mark_tsc_unstable(void);