Messages in this thread | | | Subject | Re: [PATCH 4/8] cpufreq/schedutil: sysfs capacity margin tunable | From | Steve Muckle <> | Date | Wed, 16 Mar 2016 10:55:49 -0700 |
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On 03/16/2016 03:02 AM, Juri Lelli wrote: > Hi, > > On 16/03/16 09:05, Peter Zijlstra wrote: >> On Tue, Mar 15, 2016 at 08:36:57PM -0700, Steve Muckle wrote: >>>> Then again, maybe this knob will be part of the mythical >>>> power-vs-performance slider? >>> >>> Patrick Bellasi's schedtune series [0] (which I think is the referenced >>> mythical slider) aims to provide a more sophisticated interface for >>> tuning scheduler-driven frequency selection. In addition to a global >>> boost value it includes a cgroup controller as well for per-task tuning. >>> >>> I would definitely expect the margin/boost value to be modified at >>> runtime, for example if the battery is running low, or the user wants >>> 100% performance for a while, or the userspace framework wants to >>> temporarily tailor the performance level for a particular set of tasks, etc. >> >> OK, so how about we start with it as a debug knob, and once we have >> experience and feel like it is indeed a useful runtime knob, we upgrade >> it to ABI. >> > > I tend to agree here. To me the margin is something that we need to make > this thing work and to get acceptable performance out of the box. So we > can play with it while debugging, but I consider the schedtune slider as > the way to tune the system at runtime.
Could the default schedtune value not serve as the out of the box margin?
Regardless I agree that a debug interface is the way to go for now while we figure things out.
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