Hi Sasha,
On Monday 28 Jan 2019 at 10:41:20 (-0500), Sasha Levin wrote:
From: Quentin Perret quentin.perret@arm.com
[ Upstream commit 011b27bb5d3139e8b5fe9ceff1fc7f6dc3145071 ]
Add another member to the family of per-cpu sched_domain shortcut pointers. This one, sd_asym_cpucapacity, points to the lowest level at which the SD_ASYM_CPUCAPACITY flag is set. While at it, rename the sd_asym shortcut to sd_asym_packing to avoid confusions.
Generally speaking, the largest opportunity to save energy via scheduling comes from a smarter exploitation of heterogeneous platforms (i.e. big.LITTLE). Consequently, the sd_asym_cpucapacity shortcut will be used at first as the lowest domain where Energy-Aware Scheduling (EAS) should be applied. For example, it is possible to apply EAS within a socket on a multi-socket system, as long as each socket has an asymmetric topology. Energy-aware cross-sockets wake-up balancing will only happen when the system is over-utilized, or this_cpu and prev_cpu are in different sockets.
Although I'm not really confident about the process for those AUTOSEL patches, I think this one alone won't help anybody without the other ~10 EAS patches. And I assume you definitely don't want to mark those as stable, so I'm not sure if this one is a good candidate either.
On a side note, the best description I could find of AUTOSEL with a 5 min Google search is this: https://lwn.net/Articles/750057/ Do you have any pointers to a doc where I can read up about AUTOSEL ?
Thanks, Quentin