gtpa2m30Application Programming

RPC Storage Considerations

RPC servers run in a threaded environment. You need to consider both the size of the ECB heap area and the maximum number of threads in a process. As each thread is created in a process, the heap area of the initial thread is shared with the new thread. The maximum number of threads in a process affects the size of the collective heap.

You can enter the ZCTKA ALTER command to modify heap storage values. The maximum size of the ECB heap is set by specifying the EMPS parameter. The maximum number of 4-KB frames that an ECB can acquire for heap storage is set by specifying the MMHS parameter. Specifying these parameters affects all ECBs in the TPF 4.1 system. In a threaded environment, the value in the MMHS parameter may be too small to accommodate the collective heap. You can modify the CE2MPF field in the ECB to override the value in the MMHS parameter; this will allow for the number of 4-KB frames required by the collective heap.

When a thread issues a request for heap storage, frames are attached to the initial thread. For RPC, this is the ECB that issued the rpc_server_listen API.

Note:
These frames are not released until the initial ECB exits. For RPC, this means that the server has been shut down.