Tomáš Faltín

Tomáš Faltín

I'm a computer systems researcher and Assistant Professor at Charles University, focused on building and analyzing high-performance, scalable software. My core research investigates large-scale distributed graph processing and the underlying performance mechanics of concurrent systems through rigorous analysis and benchmarking. I bring industry and academic experience from my past work at Oracle Labs and Inria Paris.

Tapestry: Revealing Wait-For Dependencies Between Application Threads

Published in PLOS, 2025

Application slowdowns that accumulate on the critical path significantly impact performance. Identifying them requires visualizing inter-thread wait-for dependencies, a task neglected by existing tools, especially regarding ad-hoc, busy-waiting synchronization. We present Tapestry, which efficiently traces these dependencies by dynamically switching between hardware watchpoints and software breakpoints. Using three use cases, we show that Tapestry is able to reveal NUMA effects and explain performance anomalies in oversubscribed and virtualized environments.

Recommended citation: Tomáš Faltin, Himadri Chhaya-Shailesh, Julia Lawall, and Jean-Pierre Lozi. 2025. Tapestry: Revealing Wait-For Dependencies Between Application Threads. In Proceedings of the 13th Workshop on Programming Languages and Operating Systems (PLOS '25). Association for Computing Machinery, New York, NY, USA, 93–100. https://doi.org/10.1145/3764860.3768339
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