Faster randomized consensus with an oblivious adversary

Two new algorithms are given for randomized consensus in a shared-memory model with an oblivious adversary. Each is based on a new construction of a conciliator, an object that guarantees termination and validity, but that only guarantees agreement with constant probability. The first conciliator assumes unit-cost snapshots and achieves agreement among n processes with probability 1 − in O(log∗ n + log(1/ )) steps for each process. The second uses ordinary multi-writer registers, and achieves agreement with probability 1− in O(log log n+log(1/ )) steps. Combining these constructions with known results gives randomized consensus for arbitrarily many possible input values using unit-cost snapshots in O(log∗ n) expected steps and randomized consensus for up to O(log n log log n) possible input values using ordinary registers in O(log log n) expected steps. Categories and Subject Descriptors

• Type: Journal
• Year: 2012
• Where: PODC
• Authors: James Aspnes
• Keywords: Conciliator, Distributed And Parallel Computing, Memory Model, Oblivious Adversary, PODC 2012