/* * linux/include/asm-i386/timex.h * * i386 architecture timex specifications */ #ifndef _ASMi386_TIMEX_H #define _ASMi386_TIMEX_H #include <linux/config.h> #include <asm/processor.h> #ifdef CONFIG_X86_ELAN # define CLOCK_TICK_RATE 1189200 /* AMD Elan has different frequency! */ #else # define CLOCK_TICK_RATE 1193182 /* Underlying HZ */ #endif /* * 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; 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 unsigned int cpu_khz; extern int read_current_timer(unsigned long *timer_value); #define ARCH_HAS_READ_CURRENT_TIMER 1 #endif