Distributed Inference
Split model across multiple GPUs or machines so it fits in VRAM and requests parallelize across devices.
Think of it like
A large jigsaw puzzle split across four tables so you can assemble it faster with four people.
Example
70B model will not fit on one A100; shard across two A100s using tensor parallelism; request takes same latency but you serve 2x throughput.
How it actually works
Tensor parallelism splits weight matrices (each GPU holds rows of weight); pipeline parallelism splits layers (GPU0 has layers 1-20, GPU1 has layers 21-40). Communication overhead (all-reduce, all-gather) can negate speedup if link is slow. Best on NVLink or InfiniBand; bad on 1Gbps Ethernet.
For product teams
Enables serving of massive models that do not fit on single GPU.
For engineers
Model partitioned during load; forward pass communicates between GPUs; orchestrator (vLLM, TensorRT-LLM) handles communication patterns.
Related
- Model Parallelism — Opposite of.
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