Danilo Krummrich
2023-Mar-16 16:39 UTC
[Nouveau] [PATCH drm-next 00/14] [RFC] DRM GPUVA Manager & Nouveau VM_BIND UAPI
Hi Oded, sorry for the late response, somehow this mail slipped through. On 2/6/23 15:48, Oded Gabbay wrote:> On Thu, Jan 19, 2023 at 7:24 AM Matthew Brost <matthew.brost at intel.com> wrote: >> Is this not an application issue? Millions of mappings seems a bit >> absurd to me. > If I look at the most extreme case for AI, assuming 256GB of HBM > memory and page mapping of 2MB, we get to 128K of mappings. But that's > really the extreme case imo. I assume most mappings will be much > larger. In fact, in the most realistic scenario of large-scale > training, a single user will probably map the entire HBM memory using > 1GB pages. > > I have also a question, could this GPUVA code manage VA ranges > mappings for userptr mappings, assuming we work without svm/uva/usm > (pointer-is-a-pointer) ? Because then we are talking about possible > 4KB mappings of 1 - 1.5 TB host server RAM (Implied in my question is > the assumption this can be used also for non-VK use-cases. Please tell > me if I'm totally wrong here).In V2 I switched from drm_mm to maple tree, which should improve handling of lots of entries. I also dropped the requirement for GPUVA entries to be backed by a valid GEM object. I think it can be used for non-VK use-cases. It basically just keeps track of mappings (not allocating them in the sense of finding a hole and providing a base address for a given size). There are basic functions to insert and remove entries. For those basic functions it is ensured that colliding entries can't be inserted and only a specific given entry can be removed, rather than e.g. an arbitrary range. There are also more advanced functions where users of the GPUVA manager can request to "force map" a new mapping and to unmap a given range. The GPUVA manager will figure out the (sub-)operations to make this happen (.e.g. remove mappings in the way, split up mappings, etc.) and either provide these operations (or steps) through callbacks or though a list of operations to the caller to process them. Are there any other use-cases or features you could think of that would be beneficial for accelerators? - Danilo> > Thanks, > Oded >
Apparently Analagous Threads
- [PATCH drm-next 05/14] drm/nouveau: new VM_BIND uapi interfaces
- [PATCH drm-next 05/14] drm/nouveau: new VM_BIND uapi interfaces
- [PATCH drm-next 05/14] drm/nouveau: new VM_BIND uapi interfaces
- [PATCH drm-next 05/14] drm/nouveau: new VM_BIND uapi interfaces
- [PATCH drm-next 05/14] drm/nouveau: new VM_BIND uapi interfaces