> -----Original Message----- > From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf > Of Deucher, Alexander > Sent: Friday, August 25, 2017 4:07 PM > To: Kuehling, Felix; amd-gfx at lists.freedesktop.org > Subject: RE: [PATCH] drm/amdgpu: Add sysfs file for VBIOS > > > -----Original Message----- > > From: Kuehling, Felix > > Sent: Friday, August 25, 2017 3:59 PM > > To: Deucher, Alexander; amd-gfx at lists.freedesktop.org > > Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS > > > > On 2017-08-25 03:40 PM, Deucher, Alexander wrote: > > >> -----Original Message----- > > >> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On > > Behalf > > >> Of Felix Kuehling > > >> Sent: Friday, August 25, 2017 3:34 PM > > >> To: amd-gfx at lists.freedesktop.org > > >> Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS > > >> > > >> I think the power measurement is a bit of a hack right now. It requires > > >> pinging the SMU twice to start and stop the measurement, and waiting > > for > > >> some time (but not too long) in between. I think if we want to expose > > >> this via hwmon, we'll need to have some kind of timer that polls it in > > >> regular intervals in the background and updates a value that can be > > >> queried through HWMon without delay. > > > I don't know that hwmon has any requirements with respect to delay. I > > think a slight delay in reading it back through hwmon is preferable to a > > background thread polling it. Regular polling may also have negative > impacts > > on performance or stability, depending on how it was validated. > > > > If an application is reading hwmon data from 4 GPUs and each query for > > power usage from each GPU takes one second, that would seriously limit > > the update frequency of the application. > > > > Maybe the first read could block long enough to get useful data. But > > subsequent reads could probably avoid blocking if we keep track of the > > time stamp of the last query. If it was very recently, we can return the > > last value. If it was long enough ago, we can get an updated value from > > the SMU. If the last query was too long ago, we start over and block for > > a second. > > Could we just set the sampling period down? If the application is polling for > instantaneous power we'd probably want a short smu sampling period > anyway. Otherwise, the application shouldnâ??t be polling so frequently in the > first place. Another alternative would be to expose the SMU interface directly. So getting the power would be something like: echo 1 > power #wait echo 0 > power cat power or: echo 2 > power # seconds to sample cat power #returns -EBUSY until the sampling period is done Alex > > Alex > > > > > Regards, > > Felix > > > > > Alex > > > > > >> Regards, > > >> Felix > > >> > > >> > > >> On 2017-08-25 11:56 AM, Deucher, Alexander wrote: > > >>>> -----Original Message----- > > >>>> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On > > >> Behalf > > >>>> Of Russell, Kent > > >>>> Sent: Friday, August 25, 2017 9:00 AM > > >>>> To: StDenis, Tom; Christian König; amd-gfx at lists.freedesktop.org > > >>>> Subject: RE: [PATCH] drm/amdgpu: Add sysfs file for VBIOS > > >>>> > > >>>> There is GPU Power usage reported through amdgpu_pm_info, > which > > >> also > > >>>> has some other information as well. I'd like that in sysfs, but I am > > unsure if > > >>>> we are allowed to due to the other information reported there. > > >>> For power and voltage, I believe there are standard hwmon interfaces. > > It > > >> would probably be best to expose it via those. For clocks/pcie, I think > you > > >> can already determine them via the existing pp sysfs interfaces. > > >>> Alex > > >>> > > >>>> Kent > > >>>> > > >>>> -----Original Message----- > > >>>> From: StDenis, Tom > > >>>> Sent: Friday, August 25, 2017 8:58 AM > > >>>> To: Christian König; Russell, Kent; amd-gfx at lists.freedesktop.org > > >>>> Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS > > >>>> > > >>>> On 25/08/17 08:56 AM, Christian König wrote: > > >>>>> Hi Kent, > > >>>>> > > >>>>> agree on the VBIOS dump file, that clearly belongs to debugsf. > > >>>>> > > >>>>> The power usage stuff I can't say much about cause I'm not deeply > > into > > >>>>> this, but keep in mind the restriction for sysfs: > > >>>>> 1. It's a stable interface. So it must be very well designed. > > >>>>> 2. Only one value per file. I think the power stuff doesn't fulfill > > >>>>> that requirement at the moment. > > >>>> What "power" stuff are we talking about? The sensors interface or > the > > >>>> pm_info or something else? > > >>>> > > >>>> Keep in mind umr uses the sensors debugfs file in --top mode. > > >>>> > > >>>> Tom > > >>>> _______________________________________________ > > >>>> amd-gfx mailing list > > >>>> amd-gfx at lists.freedesktop.org > > >>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx > > >>> _______________________________________________ > > >>> amd-gfx mailing list > > >>> amd-gfx at lists.freedesktop.org > > >>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx > > >> _______________________________________________ > > >> amd-gfx mailing list > > >> amd-gfx at lists.freedesktop.org > > >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx > > _______________________________________________ > amd-gfx mailing list > amd-gfx at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
