Visualization

Ray Compiled Graph provides visualization functionalities to help users with development and debugging.

Graph structure

To visualize the graph structure, call the visualize method after calling experimental_compile on the graph.

import ray
from ray.dag import InputNode, MultiOutputNode

@ray.remote
class Worker:
    def inc(self, x):
        return x + 1

    def double(self, x):
        return x * 2

    def echo(self, x):
        return x

sender1 = Worker.remote()
sender2 = Worker.remote()
receiver = Worker.remote()

with InputNode() as inp:
    w1 = sender1.inc.bind(inp)
    w1 = receiver.echo.bind(w1)
    w2 = sender2.double.bind(inp)
    w2 = receiver.echo.bind(w2)
    dag = MultiOutputNode([w1, w2])

compiled_dag = dag.experimental_compile()
compiled_dag.visualize()

By default, Ray generates a PNG image named compiled_graph.png and saves it in the current working directory. Note that this requires graphviz to be installed.

The visualization for the preceding code is shown below:

Note that tasks of the same actor are shown in the same color.

Execution schedule

Compiled Graph generates an execution schedule for each of the participating actors. This schedule is useful information for understanding how Ray executes the graph at runtime.

To visualize the execution schedule, set the environment variable RAY_CGRAPH_VISUALIZE_SCHEDULE=1 when running the script. For example, save the preceding code in a script named example.py, and run the following command:

RAY_CGRAPH_VISUALIZE_SCHEDULE=1 python3 example.py

When Ray executes experimental_compile, it generates a PNG image named compiled_graph_schedule.png and saves it in the current working directory. The visualization for the preceding code is shown below: