Use the EXCPVR option instead of the default EXCP option to eliminate any address translation of channel programs by the z/OS I/O supervisor (IOS) each time the channel program supervisor call is invoked.
With EXCPVR, the data areas involved in the I/O operation and the area containing the channel program are page-fixed. Therefore, address translation for the Channel Control Words (CCWs) that make up the channel programs is done only once, during TDP initialization.