# Information Security and Cryptography Research Group

## Scheduling computations with provably low synchronization overheads

### Guilherme Rito and Hervé Paulino

Journal of Scheduling, Springer International Publishing, Oct 2021.

We present a Work Stealing scheduling algorithm that provably avoids most synchronization overheads by keeping processors’ deques entirely private by default and only exposing work when requested by thieves. This is the first paper that obtains bounds on the synchronization overheads that are (essentially) independent of the total amount of work, thus corresponding to a great improvement, in both algorithm design and theory, over state-of-the-art Work Stealing algorithms. Consider any computation with work $T_1$ and critical-path length $T_{\infty}$ executed by $P$ processors using our scheduler. Our analysis shows that the expected execution time is $O(\frac{T_1}{P} + T_{\infty})$, and the expected synchronization overheads incurred during the execution are at most $O((C_{CAS} + C_{MFence}).P.T_{\infty})$, where $C_{CAS}$ and $C_{MFence}$, respectively, denote the maximum cost of executing a Compare-And-Swap instruction and a Memory Fence instruction.

## BibTeX Citation

@inproceedings{RitHer21,
author       = {Guilherme Rito and Hervé Paulino},
title        = {Scheduling computations with provably low synchronization overheads},
booktitle    = {Journal of Scheduling},
year         = 2021,
month        = 10,
publisher    = {Springer International Publishing},
}