How do you combine data, tensor, and pipeline parallelism (3D parallelism) to train a 175B model?
No single parallelism dimension trains a 175B model by itself. The art is stacking three of them onto the right hardware so the expensive communication stays on the fast links. Here is how to size each axis.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
No single parallelism dimension trains a 175B model by itself. The art is stacking three of them onto the right hardware so the expensive communication stays on the fast links. Here is how to size each axis.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
