Re: [RFC PATCH] tsc: synchronize TSCs on buggy Intel Xeon E5 CPUs with offset error

From: Peter Zijlstra
Date: Mon Nov 09 2015 - 17:02:40 EST


On Mon, Nov 09, 2015 at 01:59:02PM -0600, gratian.crisan@xxxxxx wrote:

> The Intel Xeon E5 processor family suffers from errata[1] BT81:

> +#ifdef CONFIG_X86_TSC
> + /*
> + * Xeon E5 BT81 errata: TSC is not affected by warm reset.
> + * The TSC registers for CPUs other than CPU0 are not cleared by a warm
> + * reset resulting in a constant offset error.
> + */
> + if ((c->x86 == 6) && (c->x86_model == 0x3f))
> + set_cpu_bug(c, X86_BUG_TSC_OFFSET);
> +#endif

That's hardly a family, that's just one, Haswell server.

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