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SubjectRe: [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable

* Len Brown <lenb@kernel.org> wrote:

> +config X86_INIT_MDELAY
> + int "Milliseconds to wait to de-assert INIT upon CPU startup" if SMP
> + range 0 10
> + default "10"
> + ---help---
> + This allows you to specify how long the BSP will delay
> + between asserting INIT and de-asserting INIT when starting another CPU.
> + This delay is paid on each cpu-online operation, including boot-time,
> + resume from suspend, and resume from hibernate. The the value of
> + 10 millisec was specified by Multi-Processor Spec 1.4 in 1997.
> + But modern hardware does not require any delay.

What's the cutoff for 'modern hardware' - which CPUs stopped requiring
the delay?

Also, is there any public document where the no-delay is specified for
'modern hardware'?

Thanks,

Ingo


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