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

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

[Mario Giammarco]

Hello,
I have an AMD Athlon(tm) II X4 635 Processor
on an asus M4A89TD PRO/USB3   motherboard with AMD 890FX chipset.
When I play videos on nvidia card (even on open source driver) the
video stutters and I can
see in syslog:

Feb 24 00:30:50 virtual1 kernel: [  719.834878] CPU 1 is now offline
Feb 24 00:30:50 virtual1 kernel: [  719.842450] CPU 2 is now offline
Feb 24 00:30:50 virtual1 kernel: [  719.852534] CPU 3 is now offline
Feb 24 00:30:50 virtual1 kernel: [  719.852538] SMP alternatives:
switching to UP code
Feb 24 00:30:51 virtual1 /usr/sbin/irqbalance: WARNING, didn't collect
load info for all cpus, balancing is broken
Feb 24 00:30:52 virtual1 kernel: [  722.294565] SMP alternatives:
switching to SMP code
Feb 24 00:30:52 virtual1 kernel: [  722.334866] Booting Node 0
Processor 1 APIC 0x1
Feb 24 00:30:52 virtual1 kernel: [  722.346033] LVT offset 1 assigned
for vector 0x400
Feb 24 00:30:52 virtual1 kernel: [  722.361174] Switch to broadcast mode on CPU1
Feb 24 00:30:52 virtual1 kernel: [  722.378717] microcode: CPU1: new
patch_level=0x010000db
Feb 24 00:30:52 virtual1 kernel: [  722.398515] Booting Node 0
Processor 2 APIC 0x2
Feb 24 00:30:52 virtual1 kernel: [  722.413375] Switch to broadcast mode on CPU2
Feb 24 00:30:52 virtual1 kernel: [  722.420603] microcode: CPU2: new
patch_level=0x010000db
Feb 24 00:30:52 virtual1 kernel: [  722.428782] Booting Node 0
Processor 3 APIC 0x3
Feb 24 00:30:52 virtual1 kernel: [  722.446283] Switch to broadcast mode on CPU3
Feb 24 00:30:52 virtual1 kernel: [  722.448615] microcode: CPU3: new
patch_level=0x010000db


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?
Please CC me because I am not on kernel mailing list.

Thanks in advance for any help,
Mario

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

[Mike Galbraith]

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

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

[Mario Giammarco]

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@online.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
>

Re: BUMP Cpu hotplug causes stutter on AMD platform, how can I disable it?

[Mario Giammarco]

Sorry to bump but if even kernel mailing list cannot point me to the right 
direction I do not know where to ask for help.
Is it possible that only me signalled this big hardware problem?

Thanks again,
Mario