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Exploiting Multi-Core Parallelism in Blockchain Validation and Construction

Authors Arivarasan Karmegam , Lucianna Kiffer , Antonio Fernández Anta

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LIPIcs.SEA.2026.23.pdf
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Subject Classification

ACM Subject Classification
  • Computing methodologies → Distributed algorithms
  • Computing methodologies → Parallel algorithms
  • Computing methodologies → Concurrent algorithms
Keywords
  • Block construction
  • Block execution
  • Deterministic parallelism
  • Conflict-aware scheduling

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Abstract

Blockchain validators can reduce block processing time by exploiting multi-core CPUs, but deterministic execution must preserve a given total order while respecting transaction conflicts and per-block runtime limits. This paper systematically examines how validators can exploit multi-core parallelism during both block construction and execution without violating blockchain semantics. We formalize two validator-side optimization problems: (i) executing an already ordered block on p cores to minimize makespan while ensuring equivalence to sequential execution; and (ii) selecting and scheduling a subset of mempool transactions under a runtime limit B to maximize validator reward. For both, we develop exact Mixed-Integer Linear Programming (MILP) formulations that capture conflict, order, and capacity constraints, and propose fast deterministic heuristics that scale to realistic workloads. 
Using Ethereum mainnet traces and including a Solana-inspired declared-access baseline (Sol) for ordered-block scheduling and a simple reward-greedy baseline (RG) for block construction, we empirically quantify the trade-offs between optimality and runtime. MILPs quickly become intractable as heterogeneity or core count increases, whereas our heuristics run in milliseconds and achieve near-optimal quality. For ordered-block execution, heuristic makespans are typically within a few percent of the MILP solutions (and can even surpass the MILP incumbent when the solver times out), yielding up to 1.5 speedup with p = 2 and 2.3 speedup with p = 8 over sequential execution, despite tight ordering constraints. For block construction, the heuristic achieves 99-100% of the MILP optimum reward on homogeneous workloads, and 74-100% of an LP-relaxation upper bound on heterogeneous workloads, where exact optimization often times out. The resulting block-construction throughput scales close to linearly with p, reaching up to 7.9 speedup with p = 8 in our experiments. These results demonstrate that lightweight, conflict-aware scheduling and selection can unlock substantial parallelism in blockchain validation, bridging the gap between sequential execution and the true potential of multi-core hardware.

Cite As Get BibTex

Arivarasan Karmegam, Lucianna Kiffer, and Antonio Fernández Anta. Exploiting Multi-Core Parallelism in Blockchain Validation and Construction. In 24th International Symposium on Experimental Algorithms (SEA 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 371, pp. 23:1-23:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026) https://doi.org/10.4230/LIPIcs.SEA.2026.23

Author Details

Arivarasan Karmegam
  • IMDEA Networks Institute, Madrid, Spain
  • Universidad Carlos III de Madrid, Spain
Lucianna Kiffer
  • IMDEA Networks Institute, Madrid, Spain
Antonio Fernández Anta
  • IMDEA Software Institute, Madrid, Spain
  • IMDEA Networks Institute, Madrid, Spain

Funding

This work is funded in part by MICIU/AEI /10.13039/501100011033/, ERDF, and the ESF+ under predoctoral training grant PREP2022-000373 and grant DRONAC (PID2022-140560OB-I00) and by MICIU/AEI/10.13039/501100011033 under grant CEX2024-001471-M.

Acknowledgements

We would like to thank Lioba Heimbach and the DISCO group at ETH Zurich for providing the transaction traces used in our experiments section.

Supplementary Materials

References

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