Re: Cache-aware scheduling does not work well with amd big/little cores

[Klaus Kusche]

This would need some more testing efforts,
because all my kernels are built without debugfs
(using an earlier version of Mario's patch),
and without Mario's patch and without debugfs,
I don't get any big/little scheduling at all.
So I'd need to build and test with debugfs
(tomorrow I'm on a mountain tour, perhaps later this week).

Prof. Dr. Klaus Kusche
Privat: Söllmnitz 32 d, D-07554 Gera/Söllmnitz
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klaus.kusche@xxxxxxx https://www.dhge.de

On 31/08/2026 19:29, Tim Chen wrote:
> On Mon, 2026-08-31 at 13:24 +0200, Klaus Kusche wrote:
>> Hello,
>>
>> both patches in combination seem to have the desired effect.
>>
>> But I just look at a bar graph showing the current load
>> of each core. 
>> The graph suggests that long-running CPU-intensive processes 
>> migrate to fast cores when fast cores become available.
>> And I have the impression that LTO compilations
>> finish significantly faster now.
>>
>> I don't have exact numbers or benchmarks.
> 
> Thanks for testing the fix.
> 
> If you just apply https://lore.kernel.org/lkml/20260825174112.2580942-1-tim.c.chen@xxxxxxxxxxxxxxx/,
> with default aggr_tolerance, what numbers do you see?
> 
> That will be helpful for further tuning.  Thanks.
> 
> Tim