Tuning Techniques

Following are the major tuning techniques for command procedures, arranged in order of expected improvement on performance; the most important tuning considerations are listed first. These are described in detail in this chapter.
  1. Preload frequently used command lists using the LOADCL command. Consider invoking a command list to issue LOADCL, loading the most frequently used command lists last. See Command Lists.
  2. For systems using PL/I command processors, define preinitialized environments for your frequently run PL/I programs. You can use the HLLENV LIST STATS command to help you decide how many preinitialized environments you need. See Running High-level Language Programs in a Preinitialized Environment.
  3. For systems using PL/I or C command processors, minimize or eliminate the I/O needed to find and read the runtime routines during command processor execution. See Command Processors.
  4. Preload frequently used command processors by not specifying RES=N on their CMDDEF statements in the CNMCMDU initialization member. See Command Processors.
  5. Consider using the REXX/370 compiler to compile REXX command lists. Compiled REXX command lists are more efficient than interpreted REXX command lists. See Compiled REXX/370 Command Lists.
  6. Avoid using nested command lists for subroutines where possible. See Subroutines.
  7. For systems using REXX command lists, group frequently used external functions and subroutines in REXX function packages. You can also modify the sample file CNMSJM11 to minimize the search time for NetView® system functions. See REXX Function Packages.
  8. Use task global variables instead of common global variables where possible. The processing demands of task global variables are smaller than the processing demands of common global variables. See Global Variables.
  9. If you expect to use more than 200 task or common global variables, specify the expected number of variables in the NetView constants module DSICTMOD. You can use the QRYGLOBL command to display the expected number of variables coded in DSICTMOD, as well as the actual number of variables found. See Global Variables.
  10. Consider using or adapting the AUTODROP command list (CNMS8003) to manage preloaded command lists. See Managing Command Lists with AUTODROP.