Port Constraints - 2021.2 English

Versal ACAP AI Engine Programming Environment User Guide (UG1076)

Document ID
UG1076
ft:locale
English (United States)
Release Date
2021-12-17
Version
2021.2 English

Port constraints are specified in the PortConstraints section. Constraints are grouped by port, such that one or more constraints can be specified per port.

Syntax

{
  "PortConstraints": {
    "<port name>": {
      <constraint>[,
      <constraint>...]
    }
  }
}
<port name> ::= string
<constraint> ::= buffers
               | colocated_nodes
               | not_colocated_nodes
               | colocated_ports
               | not_colocated_ports
               | exclusive_colocated_ports
               | colocated_reserved_memories
               | not_colocated_reserved_memories

Example

{
  "PortConstraints": {
    "mygraph.k1.in[0]": {
      "colocated_nodes": ["mygraph.k1"]
    },
    "mygraph.k2.in[0]": {
      "colocated_nodes": ["mygraph.k2"]
    },
    "mygraph.p1": {
      "buffers": [{
        "column": 2,
        "row": 1,
        "bankId": 2
      }]
    }
  }
}

Port Names

Ports must be specified by their fully qualified name: <graph name>.<kernel name>.<port name>. In the following example, the graph name is myGraph, the kernel name is k1, and the kernel has two ports named in[0] and out[0] (as specified in kernel1.cc). The fully specified port names are then myGraph.k1.in[0] and myGraph.k1.out[0].

class graph : public adf::graph {
private:
  adf::kernel k1;
public:
  my_graph() { 
    k1 = kernel::create(kernel1);
    source(k1) = "src/kernels/kernel1.cc";
  }
};
graph myGraph;

Anytime either of these ports are referenced in the constraints JSON file, they must be named myGraph.k1.in[0] and myGraph.k1.out[0], as shown in the various examples throughout this document.