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/* * linux/include/asm-i386/timex.h * * i386 architecture timex specifications */ #ifndef _ASMi386_TIMEX_H #define _ASMi386_TIMEX_H #include <linux/config.h> #define CLOCK_TICK_RATE 1193180 /* Underlying HZ */ #define CLOCK_TICK_FACTOR 20 /* Factor of both 1000000 and CLOCK_TICK_RATE */ #define FINETUNE ((((((long)LATCH * HZ - CLOCK_TICK_RATE) << SHIFT_HZ) * \ (1000000/CLOCK_TICK_FACTOR) / (CLOCK_TICK_RATE/CLOCK_TICK_FACTOR)) \ << (SHIFT_SCALE-SHIFT_HZ)) / HZ) /* * 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 cycles_t; extern cycles_t cacheflush_time; static inline cycles_t get_cycles (void) { #ifndef CONFIG_X86_TSC return 0; #else unsigned long eax, edx; __asm__("rdtsc":"=a" (eax), "=d" (edx)); return eax; #endif } #endif |