PyTorch 2.15 released

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PyTorch 2.15 released — it carries 3,117 commits from 583 contributors since 2.14 and promotes the rewritten NCCL backend to the default for all nccl process groups. A flight recorder that dumps state when a collective hangs was attached, and one-sided transfers and a NIXL backend were added to torch.distributed

Why it matters

NVGEMM was put into NVFP4 decode on Blackwell, folding the dequantization scale into the GEMM and removing the cost of launching a kernel per layer. float8_e4m3fn and _scaled_mm were added to MPS on Apple Silicon, with project-reported speedups of 8 times on single-row softmax, up to 21.7 times on upsample backward and more than 100 times on full-reduction norm. Python 3.10 builds and MPS support on macOS 14 were dropped and a good many of the new APIs are marked unstable — low-precision formats and failure recovery are working their way down into framework defaults

Source — Primary sources first; secondary reports are labelled “Press”

Officialpytorch.orghttps://pytorch.org/blog/pytorch-2-15/

Added in Week 44, 2026 · See that week

On the map — ⑱ AI Infrastructure Software line

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Related notes — Notes on the same axis from the same week

As code production sped up, the bottleneck moved

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