
Over five months, Kevin Mohler expanded PyTorch’s Metal backend in the pytorch/pytorch repository, focusing on GPU acceleration for Apple devices. He developed and optimized core tensor operations such as pooling, dropout, and embedding, implementing both forward and backward passes using C++ and Metal Performance Shaders. His work included adding new mathematical functions, improving numerical precision, and aligning backend behaviors for consistency across platforms. By addressing kernel-level performance and reliability, Kevin enabled broader model support and more efficient training on Apple hardware. The depth of his contributions reflects strong expertise in GPU programming, deep learning, and performance optimization within large-scale frameworks.

October 2025: Focused on expanding MPS support by delivering EmbeddingBag backward pass with per-sample weights and support for SUM, MEAN, and MAX gradient modes, enabling correct and efficient training on Apple Silicon.
October 2025: Focused on expanding MPS support by delivering EmbeddingBag backward pass with per-sample weights and support for SUM, MEAN, and MAX gradient modes, enabling correct and efficient training on Apple Silicon.
September 2025 highlights: Expanded the Metal/MPS backend on Apple hardware with new mathematical ops, native dropout support, and embedding improvements, plus a critical NaN handling fix in grid_sampler_3d. These deliverables improve model training capabilities on Apple GPUs, enhance numerical robustness, and optimize embedding workflows, driving business value through broader hardware support and more reliable results.
September 2025 highlights: Expanded the Metal/MPS backend on Apple hardware with new mathematical ops, native dropout support, and embedding improvements, plus a critical NaN handling fix in grid_sampler_3d. These deliverables improve model training capabilities on Apple GPUs, enhance numerical robustness, and optimize embedding workflows, driving business value through broader hardware support and more reliable results.
Summary for 2025-08: Strengthened PyTorch's MPS backend with targeted pooling and sampling enhancements for Apple hardware, delivering broader model support, higher numeric accuracy, and improved performance parity with CPU. Key outcomes include new 1D/2D/3D max_unpool operations for MPS, a backward pass for avg_pool3d with opmath_t precision, and the adoption of opmath_t in avg_pool3d for improved numerical stability. Added grid_sampler_3d support for MPS enabling 3D grid sampling with bilinear interpolation, plus a targeted fix to align avg_pool2d ceil_mode behavior between Metal and CPU backends. These changes were implemented via kernel-level updates and new utilities, enabling more robust 3D pooling and sampling workloads on Apple hardware and reducing cross-backend discrepancies.
Summary for 2025-08: Strengthened PyTorch's MPS backend with targeted pooling and sampling enhancements for Apple hardware, delivering broader model support, higher numeric accuracy, and improved performance parity with CPU. Key outcomes include new 1D/2D/3D max_unpool operations for MPS, a backward pass for avg_pool3d with opmath_t precision, and the adoption of opmath_t in avg_pool3d for improved numerical stability. Added grid_sampler_3d support for MPS enabling 3D grid sampling with bilinear interpolation, plus a targeted fix to align avg_pool2d ceil_mode behavior between Metal and CPU backends. These changes were implemented via kernel-level updates and new utilities, enabling more robust 3D pooling and sampling workloads on Apple hardware and reducing cross-backend discrepancies.
July 2025 monthly summary: On pytorch/pytorch, delivered substantial MPS (Metal Performance Shaders) backend improvements for Apple GPUs, including backward pass for 3D max pooling, 3D avg pooling addition, and an optimized 2D max pooling kernel for stride != 1, plus a bug fix preventing zeros in the MPS exponential function used by RNG. These changes improve GPU acceleration, compatibility, and RNG reliability, enabling faster training/inference and broader feature parity on MPS-backed deployments.
July 2025 monthly summary: On pytorch/pytorch, delivered substantial MPS (Metal Performance Shaders) backend improvements for Apple GPUs, including backward pass for 3D max pooling, 3D avg pooling addition, and an optimized 2D max pooling kernel for stride != 1, plus a bug fix preventing zeros in the MPS exponential function used by RNG. These changes improve GPU acceleration, compatibility, and RNG reliability, enabling faster training/inference and broader feature parity on MPS-backed deployments.
June 2025 monthly summary for pytorch/pytorch focusing on Metal backend acceleration for Apple devices. Implemented support for abs, expm1, and 3D max pooling (max_pool3d) using Metal Performance Shaders (MPS), expanding on-device compute coverage and performance. Key commits enabling these changes include: - e7698ff5cf40729d11df6c32c6df0a163e5d0ce0: [MPS] Move abs op to Metal (#155474) - 013cf1e3302d27de36588cf7a7130d76a5686bad: [MPS] Move expm1 op to Metal (#155611) - e0447bb5f84dca38e7515d1b1fdea42c647e5acd: Add `max_pool3d` for MPS (#156467) Technologies/skills demonstrated: - Metal and Metal Performance Shaders (MPS) integration and kernel development - Kernel design, type registrations, and dispatch/registration improvements for backend flexibility - On-device performance optimization and cross-backend compatibility (CPU/GPU dispatch strategy) Business value and impact: - Broadened PyTorch’s on-device acceleration on Apple devices, enabling faster inference for CNNs and 3D workloads while reducing CPU offload and power consumption. - Improved hardware utilization for macOS/iOS deployments and improved developer experience with broader operation coverage on Metal backend.
June 2025 monthly summary for pytorch/pytorch focusing on Metal backend acceleration for Apple devices. Implemented support for abs, expm1, and 3D max pooling (max_pool3d) using Metal Performance Shaders (MPS), expanding on-device compute coverage and performance. Key commits enabling these changes include: - e7698ff5cf40729d11df6c32c6df0a163e5d0ce0: [MPS] Move abs op to Metal (#155474) - 013cf1e3302d27de36588cf7a7130d76a5686bad: [MPS] Move expm1 op to Metal (#155611) - e0447bb5f84dca38e7515d1b1fdea42c647e5acd: Add `max_pool3d` for MPS (#156467) Technologies/skills demonstrated: - Metal and Metal Performance Shaders (MPS) integration and kernel development - Kernel design, type registrations, and dispatch/registration improvements for backend flexibility - On-device performance optimization and cross-backend compatibility (CPU/GPU dispatch strategy) Business value and impact: - Broadened PyTorch’s on-device acceleration on Apple devices, enabling faster inference for CNNs and 3D workloads while reducing CPU offload and power consumption. - Improved hardware utilization for macOS/iOS deployments and improved developer experience with broader operation coverage on Metal backend.
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