Re: RT patch and XEN

[Dong Liu <dliu.cn@gmail.com>]

On 6/27/12 7:04 PM, Sven-Thorsten Dietrich wrote:
>
> On Jun 27, 2012, at 1:52 PM, Dong Liu wrote:
>
>> Hi,
>>
>> I tried to run PREEMPT_RT patch under XEN, but running into some problem.
>>
>> My kernel is 3.4.3 with -r11 patch. XEN is 4.1.2. The kernel is running file as dom0. But as a Paravirtual (PV) domU, the system crashes normal when there is network traffic. kernel message indicates is kernel/rtmutex_common.h:75, which is,
>>
>>        BUG_ON(w->lock != lock);
>>
>> Is this a known problem?
>
> I would consider this hopeless.
>
> Xen will not get you RT performance nor full preemption, so there is no point in running RT on Xen.
>
> Use KVM
>
> Sven
>

I also thought of that, because the RT performance or full preemption 
also depends on Xen's code, scheduler and spin lock etc. But I just want 
to have a system for benchmark comparison.

Running the RT kernel as HVM guest is fine.

Thanks!

Dong