mpam/snapshot/v5.17

mpam/snapshot/v5.17

[itaru.kitayama]

Hi James,
I've been testing your snapshot in a VM on my M1 Max, but I see it can't mount the resctrl fs; is this expected?

Thanks,
Itaru.

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Re: mpam/snapshot/v5.17

[Rob Herring]

On Thu, Jun 09, 2022 at 07:55:30AM +0000, itaru.kitayama@fujitsu.com wrote:
> Hi James,
> I've been testing your snapshot in a VM on my M1 Max, but I see it 
> can't mount the resctrl fs; is this expected?

I don't think you can mount resctrl without MPAM h/w support.

Does an Apple M1 have MPAM?

Doesn't really matter because MPAM within a VM is not supported in the 
snapshot.

Rob

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RE: mpam/snapshot/v5.17

[itaru.kitayama]

Rob,
Indeed my colleague pointed that out to me as well. In the meantime, what's the best way to test the MPAM feature (8.4 optional)?

Itaru.

-----Original Message-----
From: Rob Herring <robh@kernel.org> 
Sent: Tuesday, June 14, 2022 1:44 AM
To: Kitayama, Itaru/來山 至 <itaru.kitayama@fujitsu.com>
Cc: 'james.morse@arm.com' <james.morse@arm.com>; 'linux-arm-kernel@lists.infradead.org' <linux-arm-kernel@lists.infradead.org>; Tan, Shaopeng/譚 紹鵬 <tan.shaopeng@fujitsu.com>
Subject: Re: mpam/snapshot/v5.17

On Thu, Jun 09, 2022 at 07:55:30AM +0000, itaru.kitayama@fujitsu.com wrote:
> Hi James,
> I've been testing your snapshot in a VM on my M1 Max, but I see it 
> can't mount the resctrl fs; is this expected?

I don't think you can mount resctrl without MPAM h/w support.

Does an Apple M1 have MPAM?

Doesn't really matter because MPAM within a VM is not supported in the snapshot.

Rob

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Re: mpam/snapshot/v5.17

[James Morse]

Hi Itaru,

On 6/13/22 22:59, itaru.kitayama@fujitsu.com wrote:
> Rob,
> Indeed my colleague pointed that out to me as well. In the meantime, what's the best way
> to test the MPAM feature (8.4 optional)?

I do my testing with the Fixed Virtual Platform from arm[0].
Its a bit of a pain to set up, but it configured correctly it presents MPAM MSC - although
they don't do anything as its not a performance model.

There are a ton of options, but the main two to try and enable are something like:
| cluster0.has_mpam=1
| cluster0.l3cache-mpamf_base=0x30000000

Let me know off list if you want a hand setting it up.


One day there will be hardware!


Thanks,

James

[0] https://developer.arm.com/Tools%20and%20Software/Fixed%20Virtual%20Platforms

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Re: mpam/snapshot/v5.17

[Jonathan Cameron]

On Wed, 15 Jun 2022 11:26:27 +0100
James Morse <james.morse@arm.com> wrote:

> Hi Itaru,
> 
> On 6/13/22 22:59, itaru.kitayama@fujitsu.com wrote:
> > Rob,
> > Indeed my colleague pointed that out to me as well. In the meantime, what's the best way
> > to test the MPAM feature (8.4 optional)?  
> 
> I do my testing with the Fixed Virtual Platform from arm[0].
> Its a bit of a pain to set up, but it configured correctly it presents MPAM MSC - although
> they don't do anything as its not a performance model.
> 
> There are a ton of options, but the main two to try and enable are something like:
> | cluster0.has_mpam=1
> | cluster0.l3cache-mpamf_base=0x30000000
> 
> Let me know off list if you want a hand setting it up.
> 
> 
> One day there will be hardware!

There is (and has been for several years... :) 

https://chowdera.com/2021/05/20210504023631776n.html

openEuler is carrying code for it.
https://gitee.com/openeuler/kernel/tree/openEuler-22.03-LTS/arch/arm64/kernel/mpam

> 
> 
> Thanks,
> 
> James
> 
> [0] https://developer.arm.com/Tools%20and%20Software/Fixed%20Virtual%20Platforms
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


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