Paper Overview
Field: ML Authors: Megan Frisella, Shubham Tiwari, Andy Ruan, Yi Pan, Parker Gustafson, Mat Jacob, Gilbert Bernstein, Stephanie Wang Published: 2026-06-09 arXiv: 2606.11169
Abstract
Large-scale model training increasingly relies on composing multiple parallelism strategies, such as data, pipeline, and expert parallelism, together with memory-saving optimizations like ZeRO. Deployed systems for foundation model pretraining often rely on human experts to manually design a high-level parallelism strategy then implement the corresponding low-level execution strategy, making it difficult to adapt the system to new strategies. Meanwhile, many general-purpose frameworks are more flexible but their implementations are still tied to a fixed set of common parallelism strategies, making it challenging to integrate state-of-the-art strategies. We present Piper, a user-controllable distributed training system that decouples the strategy from the runtime implementation. Piper allows users to declare a complete distributed training policy with a small number of model annotations and scheduling directives, where each directive applies a transformation on a unified global training DAG (intermediate representation). From this IR, Piper compiles per-device execution plans and executes them with a policy-agnostic distributed runtime. Piper maintains performance parity on common strategies such as ZeRO while achieving additional performance and memory-efficiency benefits on composite parallelism strategies such as DualPipe (used for DeepSeek-V3) by jointly scheduling computation and communication.
Key Points
- Problem: Current pretraining systems either require manual expert design of parallelism strategies, or are locked into a fixed set of supported strategies.
- Approach: A global training DAG IR; scheduling directives transform this IR; a compiler generates per-device plans run by a policy-agnostic runtime.
- Results: Performance parity with ZeRO-style strategies, plus extra speed and memory savings on composite strategies like DualPipe via joint compute-communication scheduling.
*Auto-collected on 2026-06-11*