Dynamic Guard-Band Features of the IBM zNext System

Abstract

The zNext system leverages robust VDD droop mitigation using DDS (digital droop sensors) and instruction throttling and robust core recovery to enable 3 tightly coupled dynamic guard band control loops. The 1st control loop protects timing by throttling, the 2nd controls VDD to protect performance, and the 3rd adds additional margin in case of recovery events. These dynamic guardband features save 18% DCM power and 10% system power enabling higher performance zNext system configurations.