As we move to large manycores, the hardware-based global checkpointing schemes that have been proposed for small shared-memory machines do not scale. Scalability barriers include global operations, work lost to global rollback, and inefficiencies in imbalanced or I/O-intensive loads. Scalable checkpointing requires tracking inter-thread dependences and building the checkpoint and rollback operations around dynamic groups of communicating processors. To address this problem, this paper introduces Rebound, the first hardware-based scheme for coordinated local checkpointing in multiprocessors with directory-based cache coherence. Rebound leverages the transactions of a directory protocol to track inter-thread dependences. In addition, it boosts checkpointing efficiency by: (i) delaying the writeback of data to safe memory at checkpoints, (ii) supporting operation with multiple checkpoints, and (iii) optimizing checkpointing at barrier synchronization. Finally, Rebound introduces distr...