Messages in this thread | | | Date | Tue, 11 Oct 2022 10:38:04 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/2] cpufreq: Update CPU capacity reduction in store_scaling_max_freq() |
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On Mon, Oct 10, 2022 at 11:46:29AM +0100, Lukasz Luba wrote: > > +CC Daniel, since I have mentioned a few times DTPM > > On 10/10/22 11:25, Peter Zijlstra wrote: > > On Mon, Oct 10, 2022 at 11:12:06AM +0100, Lukasz Luba wrote: > > > BTW, those Android user space max freq requests are not that long, > > > mostly due to camera capturing (you can see a few in this file, > > > e.g. [1]). > > > > It does what now ?!? Why is Android using this *at*all* ? > > It tries to balance the power budget, before bad things happen > randomly (throttling different devices w/o a good context what's > going on). Please keep in mind that we have ~3 Watts total power > budget in a phone, while several devices might be suddenly used: > 1. big CPU with max power ~3-3.5 Watts (and we have 2 cores on pixel6) > 2. GPU with max power ~6Watts (normally ~1-2Watts when lightly used) > 3. ISP (Image Signal Processor) up to ~2Watts > 4. DSP also up to 1-2Watts > > We don't have currently a good mechanism which could be aware > of the total power/thermal budget and relations between those > devices. Vendors and OEMs run experiments on devices and profile > them to work more predictable in those 'important to users' scenarios. > > AFAIK Daniel Lescano is trying to help with this new interface > for PowerCap: DTMP. It might be use as a new interface for those known > scenarios like the camera snapshot. But that interface is on the list > that I have also mentioned - it's missing the notification mechanism > for the scheduler reduced capacity due to user-space new scenario.
DTMP is like IPA but including random devices? Because I thought IPA already did lots of this.
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