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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-i386/timex.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-i386/timex.h')
-rw-r--r-- | include/asm-i386/timex.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/include/asm-i386/timex.h b/include/asm-i386/timex.h new file mode 100644 index 0000000..b41e484 --- /dev/null +++ b/include/asm-i386/timex.h @@ -0,0 +1,52 @@ +/* + * 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 long cpu_khz; + +#endif |