|Non-Confidential||PDF version||ARM 100052_0001_00_en|
|Home > Performance Optimization and Monitoring > HN-F performance events > HN-F counters|
Applications can bottleneck on one or more HN-Fs because they frequently target an address or a stream of addresses.
The following POCQ occupancy and request retry events are used to monitor possible performance loss in the system:
|PMU_HN_POCQ_RETRY_EVENT||The total number of requests that have been retried.|
|PMU_HN_POCQ_REQS_RECVD_EVENT||The total number of requests that the HN-F receives.|
Requests that cannot be queued in the POCQ, because of lack of credits, are retried. The HN-F responds with a RetryAck response, and the request waits for a static credit. This indicates whether the bottlenecks are caused by a lack of credits, and also shows if the latency of requests is very high.
Calculate the message retry rate as follows: