Thin Interrupt support is available since zEC12/zBC12, and proved to be efficient and  performant in numerous different test and customer shared-engine coupling facility  configurations. For CFCC running on z15, DYNDISP=THIN is now the default mode of operation for  coupling facility images that use shared processors. A zIIP$^{5}$ reduces the standard processor (CP) capacity requirements for z/OS Java, XML  system services applications, and a portion of work of z/OS Communications Server and Db2  UDB for z/OS Version 8 or later, which frees up capacity for other workload requirements. A zIIP enables eligible z/OS workloads to have a portion of them directed for execution to a  processor that is characterized as a zIIP. The zIIPs do not increase the MSU value of the  processor and so do not affect the IBM software license changes. z15 is the third generation of IBM Z processors to support SMT. z15 servers implement two  threads per core on IFLs and zIIPs. SMT must be enabled at the LPAR level and supported by  the z/OS operating system. SMT was enhanced for z15 and it is enabled for SAPs by default  (no customer intervention required). New with z/OS 2.4, the z/OS Container Extensions$^{6}$ allows deployment of Linux on Z software  components, such as Docker Containers in a z/OS system, in direct support of z/OS  workloads without requiring a separately provisioned Linux server, while maintaining overall  solution operational control within z/OS and with z/OS qualities of service. Workload deployed  in z/OS Container Extensions is zIIP eligible. zIIPs are designed for supporting designated z/OS workloads. One of the workloads is Java  code execution. When Java code must be run (for example, under control of IBM  WebSphere), the z/OS JVM calls the function of the zIIP. The z/OS dispatcher then suspends  the JVM task on the CP that it is running on and dispatches it on an available zIIP. After the  Java application code execution is finished, z/OS redispatches the JVM task on an available  CP. After this process occurs, normal processing is resumed. This process reduces the CP time that is needed to run Java WebSphere applications, which  frees that capacity for other workloads. How zIIPs work 3.5.5 IBM Z Integrated Information Processor (FC 1947) 120  IBM z15 (8561) Technical Guide 5 IBM z Systemsfi Application Assist Processors (zAAPs) are not available since z14 servers. A zAAP workload is  dispatched to available zIIPs (zAAP on zIIP capability). 6 z/OS Container Extensions require ordering the Container Hosting Foundation feature with Z systems (FC 0104).