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Re: proposed cpuctl modification

On 2023/03/09 19:21, Robert Elz wrote:
>     Date:        Thu, 9 Mar 2023 16:21:53 +0900
>     From:        Masanobu SAITOH <>
>     Message-ID:  <>
>   | Alder Lake-N? 4 E-cores share one microcode image. I have i7-12700 and it
>   | has 4 E-cores. Those 4 cores share one microcode image.
> Mine is an i9-12900KS which has 8 of them (2 groups of 4).
> Thanks for the confirmation, that is what looked to be happening, but
> I was just guessing from what I observed.  I just use intel processors
> (and others on occasion) I don't even pretend to understand them.
>   | I think your idea is the best. Thank you for your commit.
> No problem.  It was not a difficult change to make!
>   | Another solutions is that the kernel returns 0 instead of EEXIST if the
>   | version number is the same as the running microcode's version.
> Yes, I considered that one as well, but as you indicate, doing that just
> loses information, and gains nothing - the same number of sys calls (ioctl's)
> would be performed, all that would be saved is the check to see if the
> error is EEXIST when that happens (ie: peanuts).
> kre
> ps: do your E-cores ever just turn themselves off?   On mine, occasionally,
> and for no reason I can fathom, the BIOS reports there are none of them.
> (and NetBSD doesn't see them either).

I've never seen such problem on my machine.

> They come back after a power cycle.
> This is probably a BIOS issue, but ?

It might be...


                SAITOH Masanobu (

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