1. A method comprising: controlling, using a computing device, an execution order of portions of a graphical model using a control signal, where: the control signal is generated by a control initiator, the control initiator is connected to a control signal splitter for splitting the control signal into split control signals, the control signal splitter is a graphical element with a plurality of output ports; the plurality of output ports output the split control signals, the split control signals are initiated at the plurality of output ports when the control initiator issues an invocation to execute the portions of the graphical model, the graphical model is provided in a modeling environment, the modeling environment includes: a first subgraph having at least a first block, and a second subgraph having at least a second block, the first subgraph is connected to a first one of plurality of output ports of the control signal splitter, and the second subgraph is connected to a second one of the plurality of output ports of the control signal splitter; determining an order of invocation of the first subgraph and the second subgraph using data dependencies between the first subgraph and the second subgraph; invoking, by the control signal splitter, the first subgraph and the second subgraph, the invoking: using the split control signals, occurring at run-time, occurring at the determined order of invocation, honoring the data dependencies between the first subgraph and the second subgraph, and establishing an execution order among the first subgraph and the second subgraph; and executing the first subgraph and the second subgraph based on the execution order established by the control signal splitter.