Violation of Latency Constraint for Function Calls - 2020.2 English

Vitis HLS Messaging (UG1448)

Document ID
UG1448
Release Date
2020-11-24
Version
2020.2 English

Description

The tool is informing the user that the parent function contains sub-functions of different latencies.

Explanation

This message is to inform the user that the code is violating latency optimization rules. The tool is informing the user that the parent function contains sub-functions of different latencies. These sub-functions latencies will be added to the total parent latency as shown in the below code.

func1(...)
{
// latency of func1 = ~(func2+fun3) + ~(func1) = ~75
func2(..) # latency of this sub-func - 30
func3(...) # latency of this sub-func - 40
}

Solution

Consider taking into account the latency of the sub-function when applying the latency pragma.