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[ET-VK][conv2d] Fuse residual adds and activations into conv2d during lowering - #24823
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… lowering Pull Request resolved: #24808 ## Ulterior Motive Closing the DSR FP16 gap to LiteRT. DSR has 83 skip connections of the form `conv(...) + x * scale`, each lowered today to a separate `mul` and `add` dispatch. The previous commit added a conv2d epilogue that applies them inside every conv2d shader; this commit makes lowering use it. It also makes `et_vk.conv2d.with_epilogue` the single fused op for conv2d, replacing `et_vk.conv_with_clamp` there. ## Rationale **What**: A `conv2d_with_epilogue` pattern for `FusePatternsPass` that rewrites either of ``` activation(residual_op(convolution(...), residual [* scale])) activation(convolution(...)) ``` into `et_vk.conv2d.with_epilogue`, plus the op's definition and `op_registry` entry. A new `skip_fusion_patterns` compile option lets `WebGPUPartitioner` skip the pattern. **Why**: Without the pattern, no exported model reaches the epilogue. On DSR, an earlier revision of this stack shrank the Vulkan delegate from 469 to 229 operators and cut end-to-end latency 9.6% on Galaxy S23 and Pixel 8 Pro. The WebGPU runtime consumes Vulkan lowering but does not implement `et_vk.conv2d.with_epilogue`. ## Details - **Behavior** - conv2d + activation - **Before**: `FuseClampPass` rewrote it into `et_vk.conv_with_clamp`. - **After**: `et_vk.conv2d.with_epilogue`. At runtime both reach `add_conv2d` with an activation epilogue. - conv2d + residual, with or without an activation - **Before**: separate `aten.convolution`, `mul`, `add` and activation ops. - **After**: one `et_vk.conv2d.with_epilogue`. - conv1d + activation: unchanged. `Conv1dAsConv2dPass` and `FuseClampPass` still run after `FusePatternsPass`, so conv1d, including conv1d rewritten as conv2d, fuses into `et_vk.conv_with_clamp`, which stays registered for conv1d, WebGPU and existing `.pte` files. - WebGPU lowering: unchanged. `WebGPUPartitioner` skips `conv2d_with_epilogue`, so conv2d + activation still becomes `et_vk.conv_with_clamp`. - **Match** - A 2D, batch 1, FP16/FP32 `aten.convolution` (direct, pointwise, depthwise, grouped or transposed) with one user, whose input and output fit channels-packed textures. - Feeding `aten.add.Tensor`, `aten.sub.Tensor` or `aten.mul.Tensor` with a residual of the conv output's shape and dtype. The conv may be either operand of `mul`, and either operand of `add` when `alpha` is 1; it must be the first operand of `sub`. - When the residual is a `mul` of `x` and a `[1, C, 1, 1]` or `[C, 1, 1]` placeholder `scale`, and the residual op is the `mul`'s only user, `x` becomes the residual and `scale` the residual scale. The runtime binds the residual as a tensor and prepacks the scale, so when `scale` is not a constant or `x` is one, the `mul` stays separate and its output is the residual. - The residual cannot be the conv itself (`y + y` stays unfused), and a constant residual without a scale stays unfused. - `relu`, `hardtanh`, `clamp` or `leaky_relu` is fused as the activation when it is the only user of the binary op, or of the conv when there is no residual. A missing `hardtanh` bound defaults to -1 or 1. Activations with non-constant parameters, such as a `clamp` bound by a symbolic size, stay unfused. - **Partitioning**: As for the other patterns, `VulkanPartitioner` delegates a match's nodes without checking their support. The detector therefore repeats the conv's own checks (rank, batch, dtype, texture limits), so a conv that exceeds the texture limits stays on CPU unfused. - **Pattern replacement** - `replace_all_fusable_subgraphs` removes dead code after the detectors replace a match at a node, so nodes another pattern already replaced (for example the conv and relu of a quantized conv) cannot match again. - A replacement function may return `False` when it leaves the graph unchanged, as this pattern does for a constant residual. Such matches are not counted, so `FusePatternsPass` does not retrace the graph for them. - **Registry**: The residual is channels-packed texture3d like the input and output; weight, bias and scale are prepacked. - **`skip_fusion_patterns`**: a collection of pattern names; a string or an unknown name raises `ValueError`. It is serialized as a compile spec, and both the partitioner's pattern detection and `FusePatternsPass` honor it: ```python VulkanPartitioner(compile_options={"skip_fusion_patterns": {"conv2d_with_epilogue"}}) ``` - **Compatibility**: `.pte` files exported after this commit contain `et_vk.conv2d.with_epilogue` for every FP conv2d followed by an activation or a residual op, so they need a runtime that includes the previous commit. Existing `.pte` files keep loading, since `et_vk.conv_with_clamp` stays registered. - **WebGPU tests**: The op test generator and `test_conv_with_clamp.py` lowered through `VulkanPartitioner` directly; they now use `WebGPUPartitioner`. ``` schema: conv2d.with_epilogue(Tensor input, Tensor weight, Tensor? bias, SymInt[] stride, SymInt[] padding, SymInt[] dilation, bool transposed, SymInt[] output_padding, SymInt groups, Tensor? residual, Tensor? residual_scale, str residual_op, Scalar alpha, str activation, float activation_a, float activation_b) -> Tensor ``` ghstack-source-id: 469036207 Differential Revision: [D130216290](https://our.internmc.facebook.com/intern/diff/D130216290/)
🔗 Helpful Links🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/24823
Note: Links to docs will display an error until the docs builds have been completed. ⏳ No Failures, 19 PendingAs of commit 2fbdf6b with merge base e5ffebe ( This comment was automatically generated by Dr. CI and updates every 15 minutes. |
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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: #24808 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/699/base
ghstack PR head: https://github.com/pytorch/executorch/tree/gh/SS-JIA/699/head
Merge bot PR base: https://github.com/pytorch/executorch/tree/gh/SS-JIA/698/orig
Merge bot PR head: https://github.com/pytorch/executorch/tree/gh/SS-JIA/699/orig
Differential Revision: D130216290
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