Ship your Critical Section, Not Your Data: Enabling Transparent Delegation with TCLOCKS


Vishal Gupta, EPFL; Kumar Kartikeya Dwivedi, SRMIST; Yugesh Kothari, Yueyang Pan, Diyu Zhou, and Sanidhya Kashyap, EPFL


Today's high-performance applications heavily rely on various synchronization mechanisms, such as locks. While locks ensure mutual exclusion of shared data, their design impacts application scalability. Locks, as used in practice, move the lock-guarded shared data to the core holding it, which leads to shared data transfer among cores. This design adds unavoidable critical path latency leading to performance scalability issues. Meanwhile, some locks avoid this shared data movement by localizing the access to shared data on one core, and shipping the critical section to that specific core. However, such locks require modifying applications to explicitly package the critical section, which makes it virtually infeasible for complicated applications with large code bases, such as the Linux kernel.

We propose transparent delegation, in which a waiter automatically encodes its critical section information on its stack and notifies the combiner (lock holder). The combiner executes the shipped critical section on the waiter's behalf using a lightweight context switch. Using transparent delegation, we design a family of locking protocols, called TCLocks, that requires zero modification to applications' logic. The evaluation shows that TCLocks provide up to 5.2x performance improvement compared with recent locking algorithms.

OSDI '23 Open Access Sponsored by
King Abdullah University of Science and Technology (KAUST)

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@inproceedings {288562,
author = {Vishal Gupta and Kumar Kartikeya Dwivedi and Yugesh Kothari and Yueyang Pan and Diyu Zhou and Sanidhya Kashyap},
title = {Ship your Critical Section, Not Your Data: Enabling Transparent Delegation with {TCLOCKS}},
booktitle = {17th USENIX Symposium on Operating Systems Design and Implementation (OSDI 23)},
year = {2023},
isbn = {978-1-939133-34-2},
address = {Boston, MA},
pages = {1--16},
url = {},
publisher = {USENIX Association},
month = jul

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