View the Dataflow Graph - 2024.1 English

Vitis Tutorials: Getting Started

Document ID
XD098
Release Date
2024-05-30
Version
2024.1 English

The Dataflow Viewer graph illustrates the overall topology of the DATAFLOW region and shows what type of channels (FIFO/PIPO) were inferred for communication between the tasks in the DATAFLOW region. Analyzing each channel and process can be useful to resolve issues such as deadlock or poor throughput because of bad FIFO sizing. The icons at the top-right of the Dataflow viewer provide a legend for the diagram and access to settings.

The DataFlow Viewer displays the functions and the flow through the functions. After running C/RTL co-simulation, the elements of the graph are filled out with performance data, and the Process and Channel tables beneath the graph are also filled out. Without the performance data provided by co-simulation, the graph and tables will have NA values to reflect the missing values.

The Dataflow Viewer enables the following throughput analysis options:

  • The graph shows the overall topology of the DATAFLOW region and shows what type of channels (FIFO/PIPO) were inferred for communication between the tasks in the DATAFLOW region. Analyzing each channel and process can be useful to resolve issues such as deadlock or poor throughput due to bad FIFO sizing.

  • The co-simulation data helps with the FIFO sizing problem by tracking the maximum size of the FIFO during the course of the simulation and thereby giving the user a good reference point on how to size the FIFOs. In addition, when running co-simulation, automatic deadlock detection can highlight the processes and channels involved in the deadlock allowing the user to quickly narrow the focus and fix the issue.

  • In addition to FIFO sizing, the data reported after co-simulation also provides, on a per process and channel basis, the time spent stalling either waiting for input or blocked from writing output. The graph helps the user understand such issues and manage how the channels are sized to accommodate slow producers versus fast consumers and/or vice-versa. In addition, the graph is useful in understanding how reading from the input in the middle of a DATAFLOW region can impact performance. This is a fairly common scenario where performance can be impacted.