howtospark
Training

Expert parallelism (EP)

Offload / distributeParallelismReference

Distribute an MoE's experts across devices and dispatch each token to wherever its expert lives — the MoE-native way to scale out.

On the Spark

The natural axis for GLM-5.2's 256 experts; pairs with the 2-bit expert planes and pool-pruning in our 2-Spark run.

Objective
Offload / distribute
Relieves
CapacityBandwidth
Format
MoE experts sharded across devices
Granularity
Route tokens to the device holding the chosen expert
Lifecycle
PTQ · no gradients
Calibration
No calibration
Compression
None — splits across N devices
Quality
100% — same weights, sharded and recombined exactly
Hardware
All-to-all token routing across the interconnect
Runtimes
vLLMSGLang

A worked Spark recipe for this method hasn't been written yet — it lives here as a reference point in the ontology.