linux-kernel - Re: Fwd: Cpu hotplug causes stutter on AMD platform, how can I disable it?

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Message-ID: <CABQ2P6GDQjJPZ-r=OmJxRfwQDjMW63k6AX+_pQFAHvn-xf-7Aw@mail.gmail.com>
Date:	Mon, 25 Feb 2013 11:07:44 +0100
From:	Mario Giammarco <mgiammarco@...il.com>
To:	Mike Galbraith <bitbucket@...ine.de>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Fwd: Cpu hotplug causes stutter on AMD platform, how can I
 disable it?

Since ACPI I do not understand anymore who takes decision in my PC. So
you are saying that is not linux kernel but the bios that choose to
powerdown cpus.
Anyway I hope that linux kernel can overtake the bios because
obviously it can take better decisions.
BTW I am seeing in internet that the problem is very very big; I mean
that almost all amd platforms may have this problem. I am suprised
that noone before me informed kernel developers about it.

Thanks again,
Mario

2013/2/25 Mike Galbraith <bitbucket@...ine.de>:
> On Sun, 2013-02-24 at 22:59 +0100, Mario Giammarco wrote:
>
>> I have searched on internet and I see that is a problem common to
>> several AMD platforms.
>> Even in Microsoft Windows several people have the same problem and
>> they solved it disabling cool&quiet on bios. It seems that some amd
>> cpus on power saving cut off also HT bus blocking data from pcie bus
>> (!?!)
>> I have tried too and infact disabling cool&quiet improves a lot the problem.
>> But I would like to find a better solution, can I disable cpu hotplug?
>> Have you heard of this bug before?
>
> I haven't, but likely others have.  Hm.. if BIOS is shutting down your
> CPUs, I suspect that trying to ignore that in the kernel would be the
> mother of all bad ideas :)
>
> -Mike
>
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