In installations older than z14, z/TPF workload is evenly distributed across all available processors, even in low-utilization situations. This configuration causes cache and core contention with other LPARs. When z/TPF is running in a shared processor configuration, the achieved MIPS is higher when z/TPF is using a minimum set of processors. 

In low-utilization periods, z/TPF now minimizes the processor footprint by compressing TPF workload onto a minimal set of I-streams (engines), which reduces the effect on other LPARs and allows the entire CPC to operate more efficiently. 

As a consequence, z/OS and z/VM experience less contention from the z/TPF system when the z/TPF system is operating at periods of low demand. 

The supported operating systems are listed in Table 7-3 on page 260 and Table 7-4 on page 262. 

## zIIP support 

zIIPs do not change the model capacity identifier of z15 servers. IBM software product license charges that are based on the model capacity identifier are not affected by the addition of zIIPs. On a z15 server, z/OS Version 2 Release 1 is the minimum level for supporting zIIPs. 

No changes to applications are required to use zIIPs. They can be used by the following applications: 

GLYPH<SM590000> Db2 V8 and later for z/OS data serving for applications that use data Distributed Relational Database Architecture (DRDA) over TCP/IP, such as data serving, data warehousing, and selected utilities. 

GLYPH<SM590000> z/OS XML services. 

GLYPH<SM590000> z/OS CIM Server. 

GLYPH<SM590000> z/OS Communications Server for network encryption (Internet Protocol Security [IPSec]) and for large messages that are sent by HiperSockets. 

GLYPH<SM590000> IBM GBS Scalable Architecture for Financial Reporting. 

GLYPH<SM590000> IBM z/OS Global Mirror (formerly XRC) and System Data Mover. 

GLYPH<SM590000> IBM z/OS Container Extensions. 

GLYPH<SM590000> IBM OMEGAMONfi XE on z/OS, OMEGAMON XE on Db2 Performance Expert, and Db2 Performance Monitor. 

GLYPH<SM590000> Any Java application that uses the current IBM SDK. 

GLYPH<SM590000> WebSphere Application Server V5R1 and later, and products that are based on it, such as WebSphere Portal, WebSphere Enterprise Service Bus (WebSphere ESB), and WebSphere Business Integration (WBI) for z/OS. 

GLYPH<SM590000> CICS/TS V2R3 and later. 

GLYPH<SM590000> Db2 UDB for z/OS Version 8 and later. 

GLYPH<SM590000> IMS Version 8 and later. 

GLYPH<SM590000> zIIP Assisted HiperSockets for large messages. 

GLYPH<SM590000> z/OSMF (z/OS Management Facility). 

GLYPH<SM590000> IBM z/OS Platform for Apache Spark. 

GLYPH<SM590000> IBM Watsonfi Machine Learning for z/OS. 

GLYPH<SM590000> z/OS System Recovery Boost. 

