Messages in this thread | | | Subject | Re: [PATCH V2] ARM: cpuidle: Support asymmetric idle definition | From | Daniel Lezcano <> | Date | Fri, 2 Jun 2017 11:25:16 +0200 |
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On 02/06/2017 11:20, Sudeep Holla wrote: > > > On 01/06/17 12:39, Daniel Lezcano wrote: >> Some hardware have clusters with different idle states. The current code does >> not support this and fails as it expects all the idle states to be identical. >> >> Because of this, the Mediatek mtk8173 had to create the same idle state for a >> big.Little system and now the Hisilicon 960 is facing the same situation. >> >> Solve this by simply assuming the multiple driver will be needed for all the >> platforms using the ARM generic cpuidle driver which makes sense because of the >> different topologies we can support with a single kernel for ARM32 or ARM64. >> >> Every CPU has its own driver, so every single CPU can specify in the DT the >> idle states. >> >> This simple approach allows to support the future dynamIQ system, current SMP >> and HMP. >> >> It is unoptimal from a memory point of view for a system with a large number of >> CPUs but nowadays there is no such system with a cpuidle driver on ARM. >> > > While I agree this may be simple solution, but just not necessary for > systems with symmetric idle states especially one with large number of > CPUs. I don't like to see 96 CPU Idle driver on say ThunderX. So we > *must* have some basic distinction done here. > > IMO, we can't punish a large SMP systems just because they don't have > asymmetric idle states.
Can you point me in the upstream kernel a DTS with 96 cpus and using the cpuidle-arm driver ?
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