linux-kernel - Re: [PATCH v3 05/13] sched: Introduce SD_ASYM_CPUCAPACITY sched

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Message-ID: <CANRm+Cys4q9L5mM-8J2K6ds++NAW+OHh8kA+Y3JB=ei8vJWcXQ@mail.gmail.com>
Date:	Wed, 17 Aug 2016 16:42:36 +0800
From:	Wanpeng Li <kernellwp@...il.com>
To:	Morten Rasmussen <morten.rasmussen@....com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Yuyang Du <yuyang.du@...el.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Mike Galbraith <mgalbraith@...e.de>, sgurrappadi@...dia.com,
	freedom.tan@...iatek.com, keita.kobayashi.ym@...esas.com,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 05/13] sched: Introduce SD_ASYM_CPUCAPACITY
 sched_domain topology flag

2016-07-25 21:34 GMT+08:00 Morten Rasmussen <morten.rasmussen@....com>:
> 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