How do I know optimized latency mode (OLM) is working ?

To determine whether optimized latency mode (OLM) is working, verify that the values displayed in messages IST2316I and IST2317I are all non-zero.

You will need to do the following to view those messages:

1. Enter the command F vtamproc,TNSTAT,TRLE=trle_name command. This command will enable tuning statistics for the OSA-Express3, OSA-Express4S, or OSA-Express5S.

2. With traffic flowing over this OSA-Express3, OSA-Express4S, or OSA-Express5S, look for non-zero counts in messages IST2316I and IST2317I. If you see those non-zero counts, OLM is operating.

IST2316I displays the the early interrupt count overflow and the early interrupt count. This message applies to inbound data that is received on a QDIO DATAPATH device. The value represents the number of times that an OSA-Express feature that is operating in optimized latency mode signaled the host with an interrupt that indicates that no data was currently available to process, but that data that is destined to this host was received. These fields are both 0 for any QDIO DATAPATH device that is not operating in optimized latency mode.

IST2317I displays the Upper-Layer Protocol (ULP) return with no data available count overflow, and the ULP return with no data available count. This message applies to inbound data received on a QDIO DATAPATH device. The value represents the number of times that VTAM presented data to the ULP from an OSA-Express feature that is operating in optimized latency mode, and when VTAM received the ULP return, it found that there was no more data to process. These fields are both 0 for any QDIO DATAPATH device that is not operating in optimized latency mode.