Embedded Design Handbook

ID 683689
Date 8/28/2023
Public
Document Table of Contents

4.4.4.3. Performance Counter and Timer Hardware Considerations

One disadvantage to measuring performance with a performance counter is the size of the counter. The performance counter component consumes a large number of LEs on your device.

On a 3C120 device, a single performance counter component with three section counters defined in a modified standard hardware design consumes 671 logic cells (LCs), and 420 LC registers. In the same design, a single performance counter defined with seven section counters consumes 1339 logic cells and 808 LC registers. The resource usage of the performance counter component is nearly identical on all devices.

Note: Remove the performance counter from the final version of your system to save resources.

The timer consumes hardware resources, although substantially less than a performance counter. The timer also introduces an additional interrupt source in the system that impacts interrupt latency.

Note: Adding performance counters and timers can reduce fMAX.