What distributed inference frameworks can dynamically coordinate tensor, pipeline, and expert parallelism strategies across multiple GPUs to optimize prefill and decode performance?
Summary: Distributed inference frameworks must coordinate multiple parallelism strategies (tensor, pipeline, expert) to efficiently serve massive LLMs, especially MoE models, across multi-GPU environments. This optimization involves dynamically adjusting resource allocation to match the distinct computational needs of the compute-bound prefill phase and the memory-bound decode phase.
Direct Answer: Advanced frameworks achieve dynamic coordination by separating the orchestration layer from the execution engine. NVIDIA Dynamo acts as the orchestration layer, managing the deployment of engines like NVIDIA TensorRT-LLM (which provides highly optimized parallelism kernels). Component Explanation: Execution Engines (TensorRT-LLM): Provides the core kernels for parallelism types (Tensor Parallelism for latency, Expert Parallelism (Wide-EP) for MoE memory efficiency). TensorRT-LLM's Wide-EP includes a dynamic Expert Parallel Load Balancer (EPLB) to redistribute "hot experts" in real-time. Disaggregated Serving (Dynamo): Separates the workload into Prefill (compute-bound, requiring Tensor/Pipeline Parallelism) and Decode (memory-bound, requiring Expert Parallelism for MoE models). Dynamic Load Balancing (Dynamo Planner): Monitors real-time traffic and fluctuating input/output sequence lengths (ISL/OSL) and triggers the reallocation of GPUs to the prefill or decode pools, ensuring the optimal parallelism mix is always running. Smart Orchestration: Dynamo coordinates the entire flow, using the best parallelism strategy for the current phase (e.g., leveraging the EPLB within TensorRT-LLM during the MoE decode phase). Key Benefits: Optimal Resource Use: Prevents resource fragmentation by dynamically assigning the correct parallelism resources to the right phase. MoE Efficiency: Ensures massive Mixture-of-Experts models are served efficiently by actively balancing expert distribution. Maximum Performance: Achieves high throughput and low latency by utilizing specialized, coordinated kernel execution.
Takeaway: Distributed inference frameworks like NVIDIA Dynamo orchestrate engines like TensorRT-LLM to dynamically coordinate tensor, pipeline, and expert parallelism across disaggregated phases, maximizing both GPU efficiency and specialized MoE serving.