At PyTorch Conference 2026, Lu Fang, Research Scientist, and Ilina Mitra, Engineering Manager @Meta, will present a deep dive on building high-performance recommendation inference systems.
They will detail end-to-end production workflows, covering graph capture, model splitting, and serving across large-scale platforms like Facebook and Instagram. Attendees will gain technical insights into advanced optimizations for high TPS and low latency, as well as strategies for multi-accelerator support to handle diverse machine learning workloads at scale.
Register for PyTorchCon North America today: https://t.co/jBApW8nESi
#PyTorchCon @houser0ad@ilina_mitra
๐ No More TrainโInference Mismatch!
We demonstrate bitwise consistent on-policy RL with TorchTitan (training) + vLLM (inference) โ the first open-source run where training and inference numerics match exactly.
It only takes 3 steps:
1๏ธโฃ Make vLLM batch-invariant (same seq โ same output regardless of batching)
2๏ธโฃ Ensure forward passes in training use identical kernels as inference
3๏ธโฃ Add custom backward passes in PyTorch
โ Verified on Qwen3 1.7B + GSM8K:
โข batch_inv_ON (bitwise exact) โ KL=0.0, faster convergence, higher reward
โข batch_inv_OFF โ reduced reward, instability
We audited every op, imported vLLMโs fused kernels (SiLU MLPs, RMSNorm+residual), and wrote matching backward passes. Run is fully on-policy, deterministic, and reproducible.
Next:
โข Unified model code
โข torch.compile support
โข Perf tuning (current bitwise RL โ2.4ร slower)
โข Broader model + op coverage
๐ https://t.co/e0YChOkYm6
#vLLM #TorchTitan #RL #LLM #AIResearch