Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 4/01/2024
Public

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15.5.2.9.3. Transaction Probes

Transaction probes are used to measure latency or number of pending transactions on an NIU and report it as histograms. Transaction probes are placed in the MPFE and PSS NOCs in order to provide the ability to profile data traffic at key points.

Comparators are added to sort measured results into histogram bins. The threshold of each histogram bin depends on the mode:

  • In Latency mode (also called delay mode), various delayThresholds can be chosen for each comparator. Each delayThreshold value represents the number of clock cycles that a particular transaction takes from the time the request is issued to the time the response is returned.
  • In Pending transaction mode, various pendingThresholds can be chosen for each comparator. Each pendingThresholds value represents the number of requests pending on the NIU.

Refer to PSS NOC and MPFE NOC for more information.