We have found that the current process priority of incoming XCOM file transfers to HP NonStop (Tandem) is too high at a value of 170 and it competes with other processes.
I have checked the documentation and cannot find any mention of such a setting that is configurable to change the priority of the XCOM process that is handling inbound transmissions.
Release : 11.0
Component : CA XCOM Data Transport for HP NonStop IA64
HP NonStop Integrity
OS version J06.17
The behaviour is due to the priority set for the HP NonStop LISTNER process which is used by XCOM for incoming file transfers. Via the PORTCONF file configuration the launched XCOM62 process will then inherit the LISTNER process "context" and will also run under the same priority. In the r11.0 Bookshelf Product Guide see the section "Configuring the Network › CA XCOM Data Transport and TCP/IP › Remotely Initiated Transfers › Define the CA XCOM Data Transport for HP NonStop Listening Port"
By default the HP NonStop LISTNER process runs at high priority which is the advice from HP Support because it is the process responsible for starting the ECHO, FINGER, and FTP servers: HP NonStop TCP/IP Configuration and Management Manual (see page 3-4)
However if required the LISTNER process priority can be lowered. After a LISTNER restart the XCOM process will also then run at the lower priority.
NOTE: In this case for security reasons the site had disabled the default servers ftpserv, fingserv and echoserv in the PORTCONF file, so the LISTNER was only being used for XCOM and thus lowering its priority had no impact on other programs.