arXiv subjects

Marc Leinweber

Publications and source records attributed to Marc Leinweber.

3 recordsLinked to original sources

arXiv2025

Not eXactly Byzantine: Efficient and Resilient TEE-Based State Machine Replication

We propose, implement, and evaluate NxBFT, a resilient and efficient State Machine Replication protocol using Trusted Execution Environments (TEEs). NxBFT focuses on a "Not eXactly Byzantine" (NxB) operating model as a middle ground between crash and Byzantine fault tolerance. NxBFT's consensus layer is asynchronous, graph-based, leaderless, and optimized for the NxB operating model, enabling load-balancing of requests between replicas and, in fault-free cases, two network round trips between decisions. We identify fundamental issues with crash recovery due the use of TEEs in asynchrony that only can be circumvented by relying on synchrony for liveness. We provide a throughput-latency trade-off analysis of NxBFT, Chained-Damysus (rotating leader), and MinBFT (static leader) for up to 40 replicas and network round trip latencies up to 150 ms. NxBFT achieves the highest throughput in all scenarios. When small latencies are required, MinBFT and Damysus are at an advantage with Damysus benefiting from the NxB model in terms of throughput for small deployments. In contrast to leader-based approaches, NxBFT's performance is almost not impacted when actual crash faults occur.

cs.DC↗

arXiv2023

Let It TEE: Asynchronous Byzantine Atomic Broadcast with $n \geq 2f+1$

Asynchronous Byzantine Atomic Broadcast (ABAB) promises simplicity in implementation as well as increased performance and robustness in comparison to partially synchronous approaches. We adapt the recently proposed DAG-Rider approach to achieve ABAB with $n\geq 2f+1$ processes, of which $f$ are faulty, with only a constant increase in message size. We leverage a small Trusted Execution Environment (TEE) that provides a unique sequential identifier generator (USIG) to implement Reliable Broadcast with $n>f$ processes and show that the quorum-critical proofs still hold when adapting the quorum size to $\lfloor \frac{n}{2} \rfloor + 1$. This first USIG-based ABAB preserves the simplicity of DAG-Rider and serves as starting point for further research on TEE-based ABAB.

cs.DC↗

arXiv2018

Enabling Cross-Event Optimization in Discrete-Event Simulation Through Compile-Time Event Batching

A discrete-event simulation (DES) involves the execution of a sequence of event handlers dynamically scheduled at runtime. As a consequence, a priori knowledge of the control flow of the overall simulation program is limited. In particular, powerful optimizations supported by modern compilers can only be applied on the scope of individual event handlers, which frequently involve only a few lines of code. We propose a method that extends the scope for compiler optimizations in discrete-event simulations by generating batches of multiple events that are subjected to compiler optimizations as contiguous procedures. A runtime mechanism executes suitable batches at negligible overhead. Our method does not require any compiler extensions and introduces only minor additional effort during model development. The feasibility and potential performance gains of the approach are illustrated on the example of an idealized proof-ofconcept model. We believe that the applicability of the approach extends to general event-driven programs.

cs.PF↗