Agilex™ 7 M-Series FPGA Network-on-Chip (NoC) User Guide

ID 768844
Date 9/30/2024
Public
Document Table of Contents

3.6.4. NoC Performance Reports in Interface Planner

At any point during NoC initiator placement, you can interactively generate a NoC Performance Report in Interface Planner. The NoC Performance Report generation performs a static analysis of the NoC initiator and target locations to evaluate whether the placement allows your design to meet the bandwidth requirements and transaction sizes that you specify in the NoC Assignment Editor.

Note: The NoC Performance Report uses default clock frequencies when computing bandwidth capabilities. To generate a report based on actual clock frequencies, refer to the NoC Performance Report generated during the Fitter stage, as Fitter NoC Performance Reports describes.

To access the NoC Performance Report in Interface Planner, click the Reports tab, and then double-click Report NoC Performance in the Tasks pane.

The NoC Performance Report reports performance data for each initiator to target connection. You can achieve lower minimum structural latency by placing the NoC initiators and targets closer together. You can also display the congestion on the horizontal links visually in the NoC View.

To display this congestion after generating the report:

  1. Switch back to the Plan tab.
  2. Select the NoC View option.
  3. In the NoC View, right-click and enable Show NoC Congestion from the context menu.

    Any segments of the horizontal links that are congested will be highlighted in red.

Table 12.  NoC Performance Report Data
NoC Performance Report Column Description
Requested RD BW The requested read bandwidth in GB per second. This value is the same as the value that you specify in the NoC Assignment Editor, as Step 3: Make Attribute Assignments in NoC Assignment Editor describes.
Requested WR BW The requested write bandwidth in GB per second. This value is the same as the value that you specify in the NoC Assignment Editor.
Initiator placement The placement location of the initiator element.
Target placement The placement location of the target element.
Message A message indicating whether you can achieve the requested bandwidth, or whether the connection is congested; and information about the cause of the congestion. The cause of congestion is an indication of where the congestion occurs, and which other connections contribute to that congestion.
Figure 49. Sample NoC Performance Report Not Meeting Performance Targets


One possible reason that the Message reports that the current placement cannot meet the requested bandwidth is because of over-saturation of an initiator or a target. For example, if the sum of all bandwidth requirements through a particular initiator is greater than the bandwidth that the initiator can support, based on the data width and operating frequency of its fabric facing AXI4 interface. To avoid this problem, either reduce bandwidth requirements or increase bandwidth capability.

Another possible reason that the current placement cannot meet the requested bandwidth is over-saturation of the horizontal bandwidth available in the NoC. This condition is the result of multiple initiator to target connections requesting bandwidth over the same sections of the horizontal links.

Further congestion can arise for connections that overlap connections that are already congested for any of the above reasons.

Note: For important considerations when choosing initiator interface bridge placement, refer to the tables in Horizontal Bandwidth Considerations, along with tables in Hard Memory NoC Locations in Interface Planner to translate location choices into physical placements.