Question about rt-patch use in arm64 kvm host and guest o

Question about rt-patch use in arm64 kvm host and guest o

[鹏鲲]

I'm trying to use rt-ptach in arm64 kvm to improve real-time performance.
I couldn’t find useful information on the web so I think this mail
list is the most appropriate place to ask this question.

Rt-patch can use in arm64 kvm host linux and guest linux ? Where can I
find reference examples?

Thanks

Best,
Kun

Re: Question about rt-patch use in arm64 kvm host and guest o

[Ahmed S. Darwish]

On Feb 22, 2021, 鹏鲲 wrote:
> I'm trying to use rt-ptach in arm64 kvm to improve real-time performance.
> I couldn’t find useful information on the web so I think this mail
> list is the most appropriate place to ask this question.
>
> Rt-patch can use in arm64 kvm host linux and guest linux ? Where can I
> find reference examples?
>

I've read some articles on the topic last year, and the best (by far)
was this one:

  Realtime KVM
  https://lwn.net/Articles/656807

It written by Bonzini, the KVM maintainer. The includes links/references
are also very valuable.

Good luck,

--
Ahmed S. Darwish

Re: Question about rt-patch use in arm64 kvm host and guest o

[鹏鲲]

Ahmed S. Darwish <a.darwish@linutronix.de> 于2021年2月22日周一 下午4:34写道：
>
> On Feb 22, 2021, 鹏鲲 wrote:
> > I'm trying to use rt-ptach in arm64 kvm to improve real-time performance.
> > I couldn’t find useful information on the web so I think this mail
> > list is the most appropriate place to ask this question.
> >
> > Rt-patch can use in arm64 kvm host linux and guest linux ? Where can I
> > find reference examples?
> >
>
> I've read some articles on the topic last year, and the best (by far)
> was this one:
>
>   Realtime KVM
>   https://lwn.net/Articles/656807
>
> It written by Bonzini, the KVM maintainer. The includes links/references
> are also very valuable.
>
> Good luck,
>
> --
> Ahmed S. Darwish

Thank for your reply.

I have read this article carefully before, but this article focuses on
the x86 system.
I don't know if anyone has used rt-patch successfully on arm64 kvm? Or
have a lot of problems with arm64 kvm?

Best,
Kun

Re: Question about rt-patch use in arm64 kvm host and guest o

[Ahmed S. Darwish]

On Mon, Feb 22, 2021 at 05:29:47PM +0800, 鹏鲲 wrote:
>
> I have read this article carefully before, but this article focuses on
> the x86 system.
>

Most of the details in that article are not x86-specific.

> I don't know if anyone has used rt-patch successfully on arm64 kvm? Or
> have a lot of problems with arm64 kvm?
>

Maybe someone on the list can jump-in and provide their experience.

In general though, you will have to try things by yourself. Properly
configure both the host and guest kernels for preempt_rt, monitor
VMexits through "perf kvm" and try to minimize them, run cyclictest
inside and outside of the guest, and see how things goes...

And if this is an embedded device, you can also try Jailhouse.

Good luck,

--
Ahmed S. Darwish

Re: Question about rt-patch use in arm64 kvm host and guest o

[kun peng]

Ahmed S. Darwish <a.darwish@linutronix.de> 于2021年2月22日周一 下午6:13写道：
>
> On Mon, Feb 22, 2021 at 05:29:47PM +0800, 鹏鲲 wrote:
> >
> > I have read this article carefully before, but this article focuses on
> > the x86 system.
> >
>
> Most of the details in that article are not x86-specific.
>
> > I don't know if anyone has used rt-patch successfully on arm64 kvm? Or
> > have a lot of problems with arm64 kvm?
> >
>
> Maybe someone on the list can jump-in and provide their experience.
>
> In general though, you will have to try things by yourself. Properly
> configure both the host and guest kernels for preempt_rt, monitor
> VMexits through "perf kvm" and try to minimize them, run cyclictest
> inside and outside of the guest, and see how things goes...
>
> And if this is an embedded device, you can also try Jailhouse.
>
> Good luck,
>
> --
> Ahmed S. Darwish


I have tested the use of RT-Patch in host and guest os on Raspberry Pi4.
Now everything seems to be working fine.

Thanks a lot

Best,
Kun