CPROB: Checkpoint Processing with Opportunistic Minimal Recovery

—CPR (Checkpoint Processing and Recovery) is a physical register management scheme that supports a larger instruction window and higher average IPC than conventional ROB-style register management. It does so by restricting mis-speculation recovery to checkpoints created at rename, and leveraging this restriction to aggressively reclaim registers that don’t appear in checkpoints. The cost of CPR is checkpoint overhead, which is incurred when a mis-speculation occurs on an instruction for which a checkpoint was not created a priori. Here, CPR must recover to the immediately older checkpoint, squashing instructions older than the mis-speculation itself. In contrast, a ROB processor performs minimal recovery and only squashes instructions younger than the mis-speculation. CPROB is a hybrid register management scheme that preserves CPR’s aggressive reclamation while opportunistically minimizing checkpoint overhead. CPROB extends CPR to track and hold the registers needed to perform mi...

• Type: Conference
• Year: 2009
• Where: IEEEPACT
• Authors: Andrew D. Hilton, Neeraj Eswaran, Amir Roth
• Keywords: Checkpoint Overhead, Checkpoint’s Recovery Registers, Hardware, IEEEPACT 2009, Register Management Scheme