Lightweight Preemptible Functions


Sol Boucher, Carnegie Mellon University; Anuj Kalia, Microsoft Research; David G. Andersen, Carnegie Mellon University; Michael Kaminsky, BrdgAI / Carnegie Mellon University


Lamenting the lack of a natural userland abstraction for preemptive interruption and asynchronous cancellation, we propose lightweight preemptible functions, a mechanism for synchronously performing a function call with a precise timeout that is lightweight, efficient, and composable, all while being portable between programming languages. We present the design of libinger, a library that provides this abstraction, on top of which we build libturquoise, arguably the first general-purpose and backwards-compatible preemptive thread library implemented entirely in userland. Finally, we demonstrate this software stack’s applicability to and performance on the problems of combatting head-of-line blocking and time-based DoS attacks.

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@inproceedings {254360,
author = {Sol Boucher and Anuj Kalia and David G. Andersen and Michael Kaminsky},
title = {Lightweight Preemptible Functions},
booktitle = {2020 {USENIX} Annual Technical Conference ({USENIX} {ATC} 20)},
year = {2020},
isbn = {978-1-939133-14-4},
pages = {465--477},
url = {},
publisher = {{USENIX} Association},
month = jul,

Presentation Video