Papers › UPSCALE: Unconstrained Channel Pruning

UPSCALE: Unconstrained Channel Pruning

17 Jul 2023arXiv:2307.08771archive 2025-07-28

Alvin Wan, Hanxiang Hao, Kaushik Patnaik, Yueyang Xu, Omer Hadad, David Güera, Zhile Ren, Qi Shan

As neural networks grow in size and complexity, inference speeds decline. To combat this, one of the most effective compression techniques -- channel pruning -- removes channels from weights. However, for multi-branch segments of a model, channel removal can introduce inference-time memory copies. In turn, these copies increase inference latency -- so much so that the pruned model can be slower than the unpruned model. As a workaround, pruners conventionally constrain certain channels to be pruned together. This fully eliminates memory copies but, as we show, significantly impairs accuracy. We now have a dilemma: Remove constraints but increase latency, or add constraints and impair accuracy. In response, our insight is to reorder channels at export time, (1) reducing latency by reducing memory copies and (2) improving accuracy by removing constraints. Using this insight, we design a generic algorithm UPSCALE to prune models with any pruning pattern. By removing constraints from existing pruners, we improve ImageNet accuracy for post-training pruned models by 2.1 points on average -- benefiting DenseNet (+16.9), EfficientNetV2 (+7.9), and ResNet (+6.2). Furthermore, by reordering channels, UPSCALE improves inference speeds by up to 2x over a baseline export.

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Subselect apple/ml-upscale/src/upscale/pruning/pruner.py official repository ran · metamorphic tier: invariant fingerprinted licence not identified · pointer only · ac83a6a5ebd12447 · report
generate_pruned_weight apple/ml-upscale/src/upscale/pruning/pruner.py official repository ran licence not identified · pointer only · 2fd4914a885da34f · report
get_tensor_and_modules apple/ml-upscale/src/upscale/pruning/pruner.py official repository ran licence not identified · pointer only · 105db10cfa40adf4 · report
get_tensor_to_module_metadata apple/ml-upscale/src/upscale/pruning/pruner.py official repository ran · our draft was wrong licence not identified · pointer only · e0389ed8272e408a · report
group_indices_as_ranges apple/ml-upscale/src/upscale/pruning/pruner.py official repository ran · fixture could not drive it licence not identified · pointer only · d94ea0576422dcaa · report
insert_subselection apple/ml-upscale/src/upscale/pruning/pruner.py official repository unverified licence not identified · pointer only · 6c4abf4488a5ff40 · report
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1x1 ConvolutionAverage PoolingBatch NormalizationBottleneck Residual BlockConcatenated Skip ConnectionConvolutionDense BlockDense ConnectionsDepthwise ConvolutionDepthwise Separable ConvolutionDropoutEfficientNetV2Global Average PoolingInverted Residual BlockKaiming InitializationMax PoolingPointwise ConvolutionPruningReLUResidual BlockResidual ConnectionSoftmax

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