(E)JES Performance

(E)JES uses MVS cross memory services to obtain real-time information from JES and other running address spaces in the system, thereby avoiding contention for JES resources and eliminating unnecessary I/O.

In a sysplex environment, (E)JES uses XCF signaling services to perform event-driven signaling and to move information from one z/OS image to another.

(E)JES is designed for a large user base and eliminates redundant query activities by utilizing buffered "lazy update" techniques.

(E)JES uses advanced I/O techniques, including the use of zHPF on z10 processors with DS8100 DASD, MIDAWs, and a sophisticated caching algorithm that minimizes SPOOL I/O.

(E)JES can redirect a significant portion of execution resources to zIIP processors, which results in increased computing capacity and performance, as well as lower overall costs. This support is leveraged:

  • In all end-user interactive host client environments except CICS
  • In all batch scripts under TSO/E
  • When calling the (E)JES Application Programming Interface (including when used internally by the (E)JES REXX API)
  • In the JES3 global data gathering routines in the CAS server running on the JES3 global processor
  • When running (E)JES as the Operating System Interface (OSI) on the workstation component server

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