2 * x86 TSC related functions
7 #include <asm/processor.h>
9 #define NS_SCALE 10 /* 2^10, carefully chosen */
10 #define US_SCALE 32 /* 2^32, arbitralrily chosen */
13 * Standard way to access the cycle counter.
15 typedef unsigned long long cycles_t;
17 extern unsigned int cpu_khz;
18 extern unsigned int tsc_khz;
20 extern void disable_TSC(void);
22 static inline cycles_t get_cycles(void)
24 unsigned long long ret = 0;
26 #ifndef CONFIG_X86_TSC
31 #if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
37 static inline cycles_t vget_cycles(void)
40 * We only do VDSOs on TSC capable CPUs, so this shouldnt
41 * access boot_cpu_data (which is not VDSO-safe):
43 #ifndef CONFIG_X86_TSC
47 return (cycles_t) __native_read_tsc();
50 extern void tsc_init(void);
51 extern void mark_tsc_unstable(char *reason);
52 extern int unsynchronized_tsc(void);
53 extern void init_tsc_clocksource(void);
54 int check_tsc_unstable(void);
57 * Boot-time check whether the TSCs are synchronized across
60 extern void check_tsc_sync_source(int cpu);
61 extern void check_tsc_sync_target(void);
63 extern void tsc_calibrate(void);
64 extern int notsc_setup(char *);