The z13 can execute about 12% more [1.695/1.514] Instructions than the zEC12, although its Cycle Time is about 9% higher [5/5,5 GHz], but its Execution Units have almost 2x of Circuits, compared to the zEC12. With almost the same quantity of Circuits than the z14, and having the same Cycle Time [5,2 GHz], how can a z15 execute about 10% more [2.055/1.870] Instructions? This Presentation will show some of the “internal details” of z15 Cores [the Fetch, Parsing, Decode, Issue Out of Order of the Instructions to the various Execution Units and Removal In Order at the Completion Queues], based on the z15 Technical Guide and z15 Technical Introduction. As always happen on CMGs, we invite you all to Optimize Codes.

Luiz Carlos Orsoni
zOS Specialist – Systems Programming
Mairiporã, São Paulo Brazil

Mainframe Modernized