Performance Monitor FPGA IP User Guide: Agilex™ 3, Agilex™ 5, and Agilex™ 7 FPGAs

ID 817760
Date 3/31/2025
Public

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Document Table of Contents

3.1. AXI4 Traffic Limitations

The AXI4 interface has the following limitations for collecting performance metrics.
  • Not all metrics can be provided in a single run of the application.
  • Supports a maximum of 65,533 outstanding transactions for accurate latency metrics. In advanced latency mode, this is reduced to 500 outstanding transactions.
  • Maximum and minimum latency are supported only in the Advanced Latency Mode.
  • Requires no traffic gaps on read or write channels greater than 65,535 cycles to measure efficiency accurately.
  • Requires at least 2 transactions on an AXI4 subchannel to measure efficiency for the subchannel.
  • Does not support metric configuration mid traffic.
  • Reading metrics mid traffic provides an approximation rather than an exact value.
  • Supports a maximum of 64 monitors in the system.
  • Requires symmetry in RDATA and WDATA widths as well as ARID and AWID widths.