Exploiting the Mainframe zIIP Engine
No one will debate the fact that traditional approaches to mainframe integration are computationally expensive. We offer a unique TCO value proposition for mainframe customers, providing both breadth and depth of support for exploiting the IBM System z Integrated Information Processor (zIIP). The zIIP is unique because the work it performs is not measured for the purposes of calculating mainframe capacity and it has no speed restrictions. Our software has the ability to offload to the zIIP up to 99% of the mainframe integration processing for the multiple, parallel patterns of integration it supports, including Web services, SQL data access, events, and Web enablement. Its zIIP exploitation supports the broadest range of mainframe data sources, including Adabas, Db2 for z/OS, IMS DB, and VSAM, as well as mission-critical application environments such as CICS, IDMS, IMS TM and Natural. Rocket Data Virtualization does not cause IBM or other third-party code to become zIIP-enabled.
In order to appreciate the innovation underlying the zIIP exploitation of Rocket Data Virtualization, it is helpful to explore the multi-tasking environment of the mainframe in more detail. Mainframe processors are dispatched as threads through Task Control Blocks (TCBs)—but all threads are not created equal.
Within z/OS, the Workload Manager (WLM) software prioritizes TCBs. WLM helps administrators control workloads according to such considerations as quality of service (QoS) and service-level agreement (SLA) goals. The z/ OS also uses a lightweight, low-overhead kind of thread called an "enclave Service Request Block (SRB)." The zIIP specialty engine runs certain enclave SRBs that are zIIP-eligible. Those SRB workloads can run without the governing constraints put on the GPP and are free of the associated software charges.
Very few middleware products sold today were written to run in enclave SRB mode. Mainframe middleware is typically TCB-based products that are incapable of exploiting the zIIP. While most workloads running in an enclave SRB are zIIP-eligible, SVC (supervisor calls) can't be executed in an enclave SRB. This makes certain operating system functions such as I/O unavailable while in enclave SRB mode.
Rocket Data Virtualization utilizes a hybrid SRB/TCB architecture that creates a pair of threads—that is, an enclave SRB thread and a TCB thread—with the ability to run most of the code in the enclave SRB to exploit the zIIP, with the execution of the SVC calls switched over to the TCB. With this unique innovation our software maximizes zIIP utilization while avoiding any restrictions on what the application can do. We have taken steps to ensure that many workload components of a mainframe integration were made zIIP-eligible, including much of the XML/SOAP messaging processing, Open Database Connectivity (ODBC)/Java Database Connectivity (JDBC), ADO.NET processing, TCP/IP processing, tracing, and security. These kinds of CPU-intensive workloads are where the mainframe platform shines, and they can now enjoy the full unrestricted processing power of the zIIP while eliminating the processing overhead associated with integration.