[ET-VK] Allow int4 linear to execute without 8bit buffer support #10234
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…d checks for physical limits when allocating Pull Request resolved: #9974 ## Context At a high level, this diff addresses preventing the allocation of textures that exceed physical texture limits, especially in the context of running transformer models. Currently, the groupwise quantized int4 linear op implementation sets the scales and zero tensor to be a `Texture3D`. However, for i.e. transformer models that have a logit linear layer, the image extents required may exceed the maximum image extents available on the device. Exceeding the maximum image extents can lead to undefined behaviour, and therefore should be avoided. Also related, the Vulkan delegate did not properly understand the maximum image extents properly. The physical device limits has three fields that indicate maximum image extents: * `maxImageDimension1D` * `maxImageDimension2D` * `maxImageDimension3D` Currently, the delegate interprets `maxImageDimension1D` as the maximum image extent in the width axis, `maxImageDimension2D` as the maximum image extent in the height axis, and `maxImageDimension3D` as the maximum image extent in the depth axis. In reality, `maxImageDimension3D` represents "the largest dimension (`width`, `height`, or `depth`) that is guaranteed to be supported for all images created with an `imageType` of `VK_IMAGE_TYPE_3D`". To properly guard against exceeding device limits, this misconception must be rectified. As an additional consequence, the maximum image extent allowed for 3D tensors is much smaller than previously thought. An example maximum extents for Adreno 740: ``` maxImageDimension1D 16384 maxImageDimension2D 16384 maxImageDimension3D 2048 ``` Evidently, `maxImageDimension3D` is 8 times smaller than `maxImageDimension2D` or `maxImageDimension1D`. The exact ratio will be different depending on the GPU (I believe on some GPUs it might even be the same) but in general this knowledge reduces the threshold at which tensors can be represented via `Texture3D`. Anecdotally, I have also observed that on Adreno it is possible to allocate 3D images with extents that exceed `maxImageDimension3D` and accessing these textures within a compute shader works fine as well. But I will have to do some more research to determine if I am just getting lucky not being impacted by undefined behaviour, or if the reported `maxImageDimension3D` is not entirely accurate. To use texture storage for larger tensors, the `Texture2D` storage type should be used instead of `Texture3D`. ## Changes Changed the int4 linear operator to use buffer storage type for scales and zeros. The storage type is not selected dynamically in the interest of reducing the number of shader variants that willl need to be generated. Changed the int4 linear operator to use `Texture2D` for quantized weights instead of `Texture3D` which should be a perf boost as well as increasing the threshold for which texture storage can still be used. When checking if image extents are within physical limits, use `maxImageDimension3D` only instead of treating `{maxImageDimension1D, maxImageDimension2D, maxImageDimension3D}` as separate components. Before allocating a buffer or texture resource for a tensor, check that the resource fits within physical device limits. ghstack-source-id: 278225007 Differential Revision: [D72662176](https://our.internmc.facebook.com/intern/diff/D72662176/)
Pull Request resolved: #10030 ## Context Some Vulkan devices do not have support for 8-bit buffers, which is currently required to execute the int4 linear compute shader due to the prepacking shader requiring it. This diff bypasses that restriction by introducing a variant of the prepacking shader that does not need 8-bit buffers. ## Changes Introduce a variant of the int4 weight prepacking shader that interprets the tensor data as an array of `uint` instead of `uint8_t`. Each `uint` represents 4 `uint8_t` values. ghstack-source-id: 278225004 Differential Revision: [D72750897](https://our.internmc.facebook.com/intern/diff/D72750897/)
🔗 Helpful Links🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/10234
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…orch#10234) ## Context Some Vulkan devices do not have support for 8-bit buffers, which is currently required to execute the int4 linear compute shader due to the prepacking shader requiring it. This diff bypasses that restriction by introducing a variant of the prepacking shader that does not need 8-bit buffers. ## Changes Introduce a variant of the int4 weight prepacking shader that interprets the tensor data as an array of `uint` instead of `uint8_t`. Each `uint` represents 4 `uint8_t` values. Differential Revision: [D72750897](https://our.internmc.facebook.com/intern/diff/D72750897/)
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This PR was created by the merge bot to help merge the original PR into the main branch.
ghstack PR number: #10030 by @SS-JIA
^ Please use this as the source of truth for the PR details, comments, and reviews
ghstack PR base: https://github.com/pytorch/executorch/tree/gh/SS-JIA/210/base
ghstack PR head: https://github.com/pytorch/executorch/tree/gh/SS-JIA/210/head
Merge bot PR base: https://github.com/pytorch/executorch/tree/gh/SS-JIA/209/orig
Merge bot PR head: https://github.com/pytorch/executorch/tree/gh/SS-JIA/210/orig
@diff-train-skip-merge