nemo-mbridge-perf-moe-long-contextlisted
Install: claude install-skill yangwhale/CloseCrab
# MoE Long-Context Training
Stable docs: @docs/training/moe-optimization.md
Card: @skills/nemo-mbridge-perf-moe-long-context/card.yaml
## What Changes At Long Context
Once sequence length moves well past the 4K-class regime, attention memory and
activation residency become the dominant constraints. For MoE models, that
usually means you need some combination of:
- context parallelism
- selective recompute
- lower precision
- CPU offload for optimizer state
- a dispatcher and PP layout that do not waste the smaller remaining DP budget
## Rounded Scaling Patterns
### DSV3 on H100
The DSV3 long-context runs show a stable pattern:
- selective recompute works better than full recompute once you move past the
shortest contexts
- throughput stays in a fairly narrow band from mid-length through very long
contexts if CP is increased appropriately
- the trade shifts from "memory fit" to "GPU-count feasibility" as CP grows
In other words, long context does not immediately collapse utilization if the
layout is chosen well, but it does consume the DP budget very quickly.
### Qwen3-Next on GB200
Qwen3-Next behaves more like a memory-sensitive medium-scale model:
- 8K and 32K remain practical with moderate CP
- 64K is possible, but the throughput drop is noticeable and memory becomes
much tighter
- pipeline layout and grouped-GEMM improvements matter almost as much as CP
### Qwen3 235B on GB200
Qwen3 235B shows that long context can still be efficient on NVL72 systems wh