[PATCH v5 4/4] drm/amdgpu: track bo memory stats at runtime

[Christian König]

Am 23.10.24 um 14:24 schrieb Tvrtko Ursulin:
> [SNIP]
>>> To fold or not the special placements (GWS, GDS & co) is also 
>>> tangential. In my patch I just preserved the legacy behaviour so it 
>>> can easily be tweaked on top.
>>
>> Yeah, but again the original behavior is completely broken.
>>
>> GWS, GDS and OA are counted in blocks of HW units (multiplied by 
>> PAGE_SIZE IIRC to avoid some GEM&TTM warnings).
>>
>> When you accumulate that anywhere in the memory stats then that is 
>> just completely off.
>
> Ooops. :) Are they backed by some memory though, be it system or VRAM?

GDS is an internal 4 or 64KiB memory block which is only valid while 
shaders are running. It is used to communicate stuff between different 
shader stages and not even CPU accessible.

GWS and OA are not even memory, those are just HW blocks which implement 
a fixed function.

IIRC most HW generation have 16 of each and when setting up the 
application virtual address space you can specify how many will be used 
by the application.

Regards,
Christian.

>
> Regards,
>
> Tvrtko