You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
49 lines
1.1 KiB
49 lines
1.1 KiB
19 years ago
|
/*
|
||
|
|
* linux/include/asm-i386/tsc.h
|
||
|
|
*
|
||
|
|
* i386 TSC related functions
|
||
|
|
*/
|
||
|
|
#ifndef _ASM_i386_TSC_H
|
||
|
|
#define _ASM_i386_TSC_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;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
|
||
|
|
rdtscll(ret);
|
||
|
|
#endif
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
extern void tsc_init(void);
|
||
|
|
extern void mark_tsc_unstable(void);
|
||
|
|
|
||
|
|
#endif
|