A high MAXTHREADTASKS value might affect storage and performance. Each task requires additional storage for the following:

• The control blocks built by the kernel
• The control blocks and data areas required by the Run-Time Library
• System control blocks such as the TCB and RB

You can set a system-wide limit in BPXPRMxx, and then set higher limits for individual users by using the RACF® ADDUSER or ALTUSER command to specify the THREADSMAX limits on a per-user basis, as follows:

ALTUSER userid OMVS(THREADSMAX(nnnn))