Re: [PATCH 0/1] speeding up cpu_up()

From: Ingo Molnar
Date: Mon Apr 20 2015 - 03:16:07 EST



* Len Brown <lenb@xxxxxxxxxx> wrote:

> The following patch...
>
> [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable
>
> enables reducing cpu_up() time by 10ms on modern systems.
>
> This means that for every processor in the system,
> boot-time and resume-time can be reduced by 10ms per-processor.
>
> Once this patch is accepted, I'll send a subsequent patch
> to update the default delay, as appropriate.
>
> thanks,
> Len Brown, Intel Open Source Technology Center

So instead of playing games with an ancient delay, I'd suggest we
install the 10 msec INIT assertion wait as a platform quirk instead,
and activate it for all CPUs/systems that we think might need it, with
a sufficiently robust and future-proof quirk cutoff condition.

New systems won't have the quirk active and thus won't have to have
this delay configurable either.

Thanks,

Ingo
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