5.3: Simultaneous multithreading with Java workloads

The zIIP processors in a z13 system can run to two threads simultaneously in a single core while sharing certain processor resources, such as execution units and caches. This capability is known as simultaneous multithreading (SMT). The use of SMT for two threads concurrently is known as SMT mode 2.

This section describes SMT, the methods that are used to measure the effectiveness of the technology, and the results of a Java™ benchmark in CICS to demonstrate the increased capacity that is available when SMT is enabled.