Re: [patch-mm 14/33] x86_64: Consolidate tsc calibration

From: Andi Kleen
Date: Tue Jul 17 2007 - 08:56:07 EST


On Sunday 15 July 2007 18:10:55 Thomas Gleixner wrote:
> Move the TSC calibration code to tsc.c. Reimplement it so the
> pm timer can be used as a reference as well.

Why is the pm timer better than the PIT for this?

I've had mixed success with the pmtimer too.

>
> Index: linux-2.6.22-rc6-mm/include/asm-i386/tsc.h
> ===================================================================
> --- linux-2.6.22-rc6-mm.orig/include/asm-i386/tsc.h 2007-07-15 17:26:45.000000000 +0200
> +++ linux-2.6.22-rc6-mm/include/asm-i386/tsc.h 2007-07-15 17:34:42.000000000 +0200
> @@ -71,4 +71,8 @@ extern void init_tsc_clocksource(void);
> extern void check_tsc_sync_source(int cpu);
> extern void check_tsc_sync_target(void);
>
> +#ifdef CONFIG_X86_64
> +extern void tsc_calibrate(void);
> +#endif

The ifdef shouldn't be needed?

-Andi
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