We have an MAI region with a large user base (>500). During busy periods response time for panel displays are slow. A command issued under OCS responds immediately but the same command in Command Entry (CMD) is slow. MAI session response times are not impacted. After the peak period of the day response times return to normal.
Release : 5.0
Component : CA SOLVE:Access Session Management
The region has a concurrent panel send limit (SYSPARMS PANLBUFF) that throttles the number of sends so that VTAM does not experience storage problems. The default limit is 40. In regions with a large user community and high menu activity this may result in queueing of sends. You can confirm panel throttling is happening by issuing the command SHOW XPB=59A. If this thread is running then panel throttling is happening.
To resolve the panel buffer throttling issue set the SYSPARMS PANLBUFF to a higher value.
A SYSPARMS PANLBUFF=nnn can be entered to dynamically change the limit, where nnn is a value that is approximately 10 per cent of the number of users.
The SYSPARMS PANLBUFF=nnn command should be included in the NMREADY procedure for the SOLVE region(s) with a large number of users.