XeGPU RFC update: Add matrix_desc and operations for share local memory access #1092
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Jianhui-Li
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Jianhui-Li
changed the title
Garra1980
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Jul 8, 2025
docs/rfcs/XeGPU.md
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| @@ -329,6 +329,20 @@ Attribute `Memory_kind` describes the memory kind. "global" means the global mem | |||
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| `nbarrier` and `fence` operations lower to uniform instructions, so there is no need to specify the `sg_map`. | |||
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| ## XeGPU operations to access share local memory | |||
| Users must create `matrix_desc` to hold a matrix in the share local memory. The matrix must be row-major. The matrix can attach a attribute for its memory layout, for example, a blocked layout or just original non-blocked row-major layout (aka. linear layout). | |||
| User can get a subview of an existing `matrix_desc` to get a new `matrix_desc`, potentially having a stride. Then user can use load_matrix and store_matrix to move the matrix data between share local memory and vectors (registers). The matrix is typically 2d and but can be multi-dimension. XeGPU's load_matrix and store_matrix works at workgroup level only. It uses xegpu.layout to describe how the matrix is decomposed to data fragments and maps to work items. The workgroup level operation loads the entire matrix to vector. | |||
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Since we're talking about WG-level here I think #1033 should me merged before this one
akroviakov
reviewed
Jul 11, 2025
docs/rfcs/XeGPU.md
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| // Subview for DPAS tile shape | ||
| %ma = xegpu.matrix_desc_subview %m | ||
| : matrix_desc<32x256xf16> -> matrix_desc<256x32xf16, @block=[16, 16], #dpas_t_inst> |
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A <256x32> subview of <32x256>? Is it a "transposed view"? If so, shouldn't there be strides for subview result?
akroviakov
reviewed
Jul 11, 2025
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