On Wed, May 22, 2024 at 02:35:21PM +0530, Shivnandan Kumar wrote: > > > On 5/22/2024 1:58 PM, Krzysztof Kozlowski wrote: > > On 22/05/2024 10:15, Shivnandan Kumar wrote: > > > Update zone1_thres_count to 3 from 16 so that > > > driver can reduce bus vote in 3 sample windows instead > > > of waiting for 16 windows. This is in line with downstream > > > implementation. > > > > > > > This might make bwmon quite jittery. I don't think downstream is the > > source of truth here. Please provide some measurements *on mainline tree*. > > > > Hi Krzysztof, > > The 16-window (64 ms) waiting time is too long to reduce the bus vote. > At higher FPS, there will be multiple frames in 64ms e.g. 4 frames at 60FPS > in 64ms. Hence, delay of 64ms in decision making will lead to higher power > regression. I’ve tested this change for 4K video playback on mainline tree, > and there’s a significant power-saving. > As requested by Krzysztof already, update your commit message to capture such motivation. Please read and follow this: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes > I propose to make it a tunable,so that user space can tune it > based on runtime depending on fps. > I presume that in e.g. Android there could be some sort of power HAL that tweaks this value dynamically? In a general purpose system, how do we make sure that this value stays relevant for multiple types of use cases? > USECASE zone1_thres_count=16 zone1_thres_count=3 > 4K video playback 236.15 mA 203.15 mA 4k video playback is a fairly specific (and generally unusual) use case. Is there any impact (negative or positive) for other use cases/workloads? Regards, Bjorn > > Thanks, > Shivnandan > > > Best regards, > > Krzysztof > >
