Messages in this thread | | | Date | Mon, 20 Apr 2015 09:13:06 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable |
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* 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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