Re: [Xen-devel] Status of FLR in Xen 4.4

[Matthias <matthias.kannenberg@xxxxxxxxxxxxxx>]

Hi Sander,

thanks for the advice, I have actually no rcu stalls when i use the no-cpuidle function. Do you have a little more insight on what is actually causing this behaviour and if there is a better solution then this option, cause I don't want to sacrifice my C-states (I would assume this makes the overall server more power hungry?).

Does this has something to do with the new tickless-kernel options in the newer kernel, or is this really only an apci incompatibility with xen?

Thanks!

2013/9/27 Sander Eikelenboom <linux@xxxxxxxxxxxxxx>

Hi Matthias,

Have you tried adding "no-cpuidle" on the xen/hypervisor commandline in grub ?

--
Sander

Friday, September 27, 2013, 7:07:33 PM, you wrote:

> Hi Konrad,

> good call! I was able to reproduce the error with the 3.12-rc2 kernel, got
> a lot of information with the new NMI traces (log attached), but since I'm
> not a xen hacker I don't really know how to continue from here. So I might
> add this to the original post and maybe someone can help me. After all the
> error persists for half a year now and besides 2 kernel version / .config
> Combinations (a 3.8.2 and a 3.6.something) I could never trace this issue
> back (even with bisecting the .config because at some point it seemed
> random).


> 2013/9/27 Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

>> On Thu, Sep 26, 2013 at 07:59:40PM +0200, Matthias wrote:
>> > I'm currently on a vanilla 3.8.2 kernel because this is the only >3.4
>> > kernel I found which doesn't give me this issue:
>> > http://lists.xen.org/archives/html/xen-users/2013-02/msg00114.html
>>
>> So v3.12 (or rather the latest and greaters of the Linus) has the mechanism
>> for the NMI - so you can actually see what is causing the stall.
>>

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