Messages in this thread | | | Date | Thu, 2 Jun 2022 10:16:23 +0100 | Subject | Re: [PATCH 3/3] thermal/sysfs: Remove cooling device sysfs statistics | From | Lukasz Luba <> |
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On 6/2/22 09:37, Daniel Lezcano wrote: > > Hi Lukasz, > > [Adding Todd] > > On 01/06/2022 17:33, Lukasz Luba wrote: >> Hi Daniel, >> >> >> On 6/1/22 16:14, Daniel Lezcano wrote: >>> The statistics are for debugging purpose and belong to debugfs rather >>> than sysfs. As the previous changes introduced the same statistics in >>> debugfs, those in sysfs are no longer needed and can be removed. >> >> I just want to let you know that in current Android kernels we cannot >> even compile the kernel with CONFIG_DEBUG_FS. > > Right, it makes sense. Precisely, with the sysfs stats they are always > compiled in for the Android kernel and is a problem for low memory > systems. While debugfs can fulfill its purpose in the developement and > will be removed in production systems.
True.
> >> I have this pain with >> Energy Model there... Some vendors might see useful info via this >> sysfs interface in bring-up of the SoC. > > Well alternatively, information can be extracted from procfs in the > device-tree description. > > What prevents to add energy information in sysfs now that the energy > model is per device ?
Probably nothing, but we need strong need. I have proposed this a few times internally, but this must have a requirement. If a user-space tool would ask for it, then I could send a patch exposing the sysfs. So far we have only one user-space tool, which suffers the missing debugfs EM dir: LISA (but we are working on a workaround for it). If you have a tool or plan to have such, which uses EM, please let me know. I'm gathering the requirements.
> >> I don't know if there are user-space tools tracking this >> information via sysfs. We probably should check that. >> >> I agree that these statistics look more like debug info, rather than >> something useful for control. >> >> Furthermore, we have trace events for the cooling state changes, which >> should be good enough for bring-up and experiments. >> >> I don't have strong preferences here. I tend to agree to remove this >> interface if there are no user-space tools using it. > > I agree userspace can also get information about the transition but the > goal of the debugfs is also add information about thermal internals like > average temperature at mitigation time, min and max, timings, etc ... > >
I see, it makes sense. Let's see if Todd and Android folks don't use this thermal sysfs stats, so we could remove them.
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