SerialLite II IP Core User Guide

ID 683179
Date 7/13/2021
Public
Document Table of Contents

2.8.16.1. Improving Performance

Performance is the factor that depends most on what other logic exists in the device.

If the SerialLite II IP core is competing with other logic for routing resources, inefficient routing could compromise speed.

Table 16.  Factors Comprising Speed
Factors Description
Feature selection
These features impact speed more significantly:
  • Lane count—running more lanes more slowly reduces the operating frequency required (but uses more logic resources).
  • CRC—the CRC generation and checking logic degrades performance and latency. In particular, if you are using CRC-32, evaluate carefully whether the extra protection over CRC-16 is really worthwhile, because CRC-16 has less impact on speed.
  • Receive FIFO buffer size—large FIFO buffers increase fanout and may require longer routing to extend further inside the device.

Your system may require some of these features, but if any are optional or can be reconsidered, this may help your performance. Before making any changes, verify that the feature you want to change is in the critical speed path.

Running different seeds

If your first attempt at hitting performance is close to the required frequency, try running different placement seeds. This technique often yields a better result.

For information on seed specification and improving speed refer to the Command-Line Scripting and the Design Space Explorer chapters in the Quartus Prime Handbook.

Limiting fanout

Depending on the number of lanes and the size of memories you choose, fanout can impact performance.

Limiting the fanout during synthesis causes replication of high-fanout signals, improving speed. If high-fanout signals are the critical path, limiting the fanout allowed can help.

Refer to the Quartus Prime Handbook for more information on limiting fanout.

Floorplanning

The SerialLite II IP core does not come with any placement constraints. The critical paths depend on where the Fitter places SerialLite II logic in the device, as well as the other logic in the device. You can use standard floorplanning techniques to improve performance.

Refer to the Quartus Prime Handbook for more information on floorplanning.