On 3/24/23 14:19, Michal Koutný wrote:
On Fri, Mar 24, 2023 at 02:32:50PM +0000, Will Deacon will@kernel.org wrote:
So approaches such as killing tasks or rejecting system calls tend not to work as well, since you inevitably get divergent behaviour leading to functional breakage rather than e.g. performance anomalies.
What about temporary performance drop from 100% to 0% aka freezing the tasks for the duration of the mismatching affinity config?
That can be a lot of extra work to freeze it. I will prefer something simpler.
Without this patch, I believe it will lead to a cpumask of 0 which will cause the scheduler to pick a fallback cpu. It looks like the fallback code may be able to pick up the right cpu or it may panic the system (less likely).
Cheers, Longman
Having said that, the behaviour we currently have in mainline seems to be alright, so please don't go out of your way to accomodate these SoCs.
I see. (Just wondering what you think about the fourth option above.)
Thanks, Michal