Multicast Support - Multicast Support - 2026.1 English - UG1079

The graph supports various multicast scenarios. These include the following:

• from a buffer to multiple buffers
• from stream to multiple streams
• from input_plio to multiple buffers, and so on.

This section lists the supported types of multicast from a single source to multiple destinations. For additional details on input_plio/output_plio, and input_gmio/output_gmio, refer to Graph Programming Model.

When multiple streams connect to the same source, data transfers to all destination ports simultaneously when all destinations are ready to receive. This can cause stream stall or design hang if the FIFO depth of the stream connections are not deep enough.

The following multicast example shows scenario number 10 from the preceding table. Source and both destinations are stream.

This graph.h code snippet defines two sub-graphs _graph0 and _graph1 within the top graph (top_graph). This ensures simultaneous data transfer to all destination ports.

class _graph0: public adf::graph {
private:
    adf::kernel kr;
public:
    adf::port<input> instream;
    adf::port<output> outstream;
    _graph0() {
        kr = adf::kernel::create(compute0);
        adf::runtime<ratio>(kr) = 0.9;
        adf::source(kr) = "compute0.cc";
        adf::connect<adf::stream> n0(instream, kr.in[0]);
        adf::connect<adf::stream> n1(kr.out[0], outstream);
    }
};

class _graph1: public adf::graph {
private:
    adf::kernel kr;
public:
    adf::port<input> instream;
    adf::port<output> outstream;
    _graph1() {
        kr = adf::kernel::create(compute1);
        adf::runtime<ratio>(kr) = 0.9;
        adf::source(kr) = "compute1.cc";
        adf::connect<adf::stream> n0(instream, kr.in[0]);
        adf::connect<adf::stream> n1(kr.out[0], outstream);
    }
};

class top_graph: public adf::graph {
private:

public:
    _graph0 g0;
    _graph1 g1;
    adf::input_plio  instream;
    adf::output_plio outstream0;
    adf::output_plio outstream1;
    top_graph()
    {
        instream   = adf::input_plio::create("aie_brodcast_0_S_AXIS",
                         adf::plio_32_bits,
                         "data/input.txt");
        outstream0 = adf::output_plio::create("aie_graph0_outstream",
                         adf::plio_32_bits,
                         "data/output0.txt");
        outstream1 = adf::output_plio::create("aie_graph1_outstream",
                         adf::plio_32_bits,
                         "data/output1.txt");

        adf::connect<adf::stream> n0(instream.out[0], g0.instream);
        adf::connect<adf::stream> n1(instream.out[0], g1.instream);
        adf::connect<adf::stream> n2(g0.outstream, outstream0.in[0]);
        adf::connect<adf::stream> n3(g1.outstream, outstream1.in[0]);
    }
};

In this graph.cpp code snippet, the graph calls are invoked from the top graph, so all sub-graphs receive the same data simultaneously.

top_graph top_g;

#if defined  (__AIESIM__) || defined(__X86SIM__)
int main () {
        top_g.init();
        top_g.run(3);
        top_g.wait();
        top_g.end();
        return 0;
}
#endif