1. [Publications](/publications) 2. A Scalable Architecture for Ordered Parallelism # A Scalable Architecture for Ordered Parallelism ![Publication image](/sites/default/files/styles/wide/public/default_images/default.jpeg?itok=qUFsuJCP "Publication image") We present Swarm, a novel architecture that exploits ordered irregular parallelism, which is abundant but hard to mine with current software and hardware techniques. In this architecture, programs consist of short tasks with programmer-specified timestamps. Swarm executes tasks speculatively and out of order, and efficiently speculates thousands of tasks ahead of the earliest active task to uncover ordered parallelism. Swarm builds on prior TLS and HTM schemes, and contributes several new techniques that allow it to scale to large core counts and speculation windows, including a new execution model, speculation-aware hardware task management, selective aborts, and scalable ordered commits. We evaluate Swarm on graph analytics, simulation, and database benchmarks. At 64 cores, Swarm achieves 51–122× speedups over a single-core system, and outperforms software-only parallel algorithms by 3–18×. ## Authors Mark C. Jeffery (MIT) Suvinay Subramanian (MIT) Cong Yang (MIT) [Joel Emer](/person/joel-emer) Daniel Sanchez (MIT) ## Publication Date Saturday, December 5, 2015 ## Published in [International Symposium on Microarchitecture (MICRO)](https://ieeexplore.ieee.org/document/7856601) ## Research Area [Computer Architecture](/research-area/computer-architecture) ## External Links [IEEE Digital Library](https://ieeexplore.ieee.org/document/7856601) ## Uploaded Files [Published manuscript](https://d1qx31qr3h6wln.cloudfront.net/publications/MICRO_2015_Swarm.pdf "Open file in new window")920.25 KB ## Copyright This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to .