Re: [PATCH v3 05/13] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag
From: Wanpeng Li
Date: Wed Aug 17 2016 - 04:43:00 EST
2016-07-25 21:34 GMT+08:00 Morten Rasmussen <morten.rasmussen@xxxxxxx>:
> Add a topology flag to the sched_domain hierarchy indicating the lowest
> domain level where the full range of cpu capacities is represented by
> the domain members for asymmetric capacity topologies (e.g. ARM
> big.LITTLE).
>
> The flag is intended to indicate that extra care should be taken when
> placing tasks on cpus and this level spans all the different types of
> cpus found in the system (no need to look further up the domain
> hierarchy). This information is currently only available through
> iterating through the capacities of all the cpus at parent levels in the
> sched_domain hierarchy.
>
> SD 2 [ 0 1 2 3] SD_ASYM_CPUCAPACITY
>
> SD 1 [ 0 1] [ 2 3] !SD_ASYM_CPUCAPACITY
>
> cpu: 0 1 2 3
> capacity: 756 756 1024 1024
>
> If the topology in the example above is duplicated to create an eight
> cpu example with third sched_domain level on top (SD 3), this level
> should not have the flag set (!SD_ASYM_CPUCAPACITY) as its two group
> would both have all cpu capacities represented within them.
I didn't find the place where set SD_ASYM_CPUCAPACITY to any SDs in
this patchset, but you have testing result in cover letter, where I
miss?
Regards,
Wanpeng Li