X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=include%2Fasm-i386%2Ftimex.h;h=292b5a68f6271b08b410d19197e3434f654e517f;hb=9464c7cf61b9433057924c36e6e02f303a00e768;hp=3666044409f06c6c2ec0c1ee6ba45d9dbeb1cd50;hpb=41689045f6a3cbe0550e1d34e9cc20d2e8c432ba;p=linux-2.6.git diff --git a/include/asm-i386/timex.h b/include/asm-i386/timex.h index 366604440..292b5a68f 100644 --- a/include/asm-i386/timex.h +++ b/include/asm-i386/timex.h @@ -6,8 +6,8 @@ #ifndef _ASMi386_TIMEX_H #define _ASMi386_TIMEX_H +#include #include -#include #ifdef CONFIG_X86_ELAN # define CLOCK_TICK_RATE 1189200 /* AMD Elan has different frequency! */ @@ -16,6 +16,39 @@ #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