The ENQ/RESERVE/DEQ monitor does not use common virtual storage below 16M. The filter table and main table are in ESQA.

The monitor uses system resources while collecting data. IBM® recommends that you do not run the monitor continuously during normal production work. While running the monitor you might observe high CPU in address spaces that issue many ENQ/RESERVE/DEQ requests.

The monitor starts with 200 buffers in private storage. It can be expanded if more storage is required. Each buffer is 4K is size. It contains a header and 30 logical records.

The number of buffers depends on the numbers of events to trace and on the speed of the output device. A counter of lost events is maintained by the monitor and is displayed with the MODIFY L command. An indication of lost event is also written in the output data set. See Monitor physical output record.

The main program writes the buffers on the sequential data sets using the macros WRITE - CHECK for each physical record and executes a TCLOSE after each buffer is written to the sequential data set. If 300 ENQ/DEQs are generated per second, 10 buffers will be written out in one second. This causes 10 I/O requests to the output data set. The data set can be allocated on a volume with DFW (DASD FAST WRITE) option active if the device cannot keep up with the I/O requests.

If the data collected in the dataspace is good enough for the analysis, specify the output data sets as DUMMY.