Re: [PATCH] powerpc: Enable generic cpu idle-loop
From: Vaibhav Jain <hidden>
Date: 2023-08-21 05:10:30
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Thanks for looking at this patch Mpe. Michael Ellerman [off-list ref] writes:
Vaibhav Jain [off-list ref] writes:quoted
This minor patch enables config option GENERIC_IDLE_POLL_SETUP for arch powerpc. This should add support for kernel param 'nohlt'.Which is named after an 8086 instruction :), but oh well.
Thanks. This is an interesting trivia :)
quoted
Powerpc kernel also supports another kernel boot-time param called 'powersave' which can also be used to disable all cpu idle-states and forces CPU to an idle-loop similar to what cpu_idle_poll() does. This patch however makes powerpc kernel-parameters better aligned to the generic boot-time parameters.It would be nice if we could make our powersave=off parameter just enable this generic logic. Have you looked at if that's possible? At a glance it looks like it should be, when cpu_idle_force_poll is true do_idle() never calls cpuidle_idle_call(), so the cpuidle drivers are never invoked.
Thanks for suggesting this and it looks like a simple fix to arch/idle.c code. I have posted a v2 with the needed change on the mailing list at https://lore.kernel.org/all/20230821045928.1350893-1-vaibhav@linux.ibm.com (local) -- Cheers ~ Vaibhav