AN 1003: Multi Memory IP System Resource Planning: for Intel Agilex® 7 M-Series FPGAs

ID 788295
Date 11/22/2023
Public
Document Table of Contents

5.13. Example: 2x2 HBM Crossbars

Consider a scenario of 2x2 HBM crossbars using the layout that Recommended NoC Design Topologies describes. With 64 byte, random read traffic, significant congestion develops on the NOC, some initiators hit their maximum outstanding transaction limit, and the initiators on the sides are starved.

You can alleviate the problem significantly by increasing the transaction size. Read Throughput for Each Initiator Versus Transaction Size illustrates throughput on each initiator, with different values of transaction size.

Figure 38. Read Throughput for Each Initiator Versus Transaction Size


By increasing transaction size, you can make the accesses at the memory controller less random over short sequences which greatly increases memory controller efficiency. You can also reduce the number of tracked transactions, so the initiators are not limited by the maximum number of outstanding transactions.