renode.md

• Software Emulation with Renode
• Installation
• Running Unit Tests
  • Under the hood of the Testing Infrastructure
• Running a non-test Binary with Renode
• Useful External Links for Renode and Robot Documentation

Software Emulation with Renode

TensorFlow Lite Micro makes use of Renode to for software emulation.

Here, we document how Renode is used as part of the TFLM project. For more general use of Renode, please refer to the Renode documentation.

You can also read more about Renode from a publicly available slide deck.

Installation

Renode can be installed and used in a variety of ways, as documented in the Renode README. For the purpose of Tensorflow Lite Micro, we make use of the portable version for Linux.

Portable renode will be automatically installed when using the TfLite Micro Makefile to tensorflow/lite/micro/tools/make/downloads/renode.

The Makefile internally calls the renode_download.sh script:

tensorflow/lite/micro/tools/make/renode_download.sh tensorflow/lite/micro/tools/make/downloads

Running Unit Tests

All the tests for a specific platform (e.g. bluepill) can be run with:

make -f tensorflow/lite/micro/tools/make/Makefile TARGET=bluepill test

• This makes use of the robot framework from Renode.
• Note that the tests can currently not be run in parallel.
• It takes about 25 second to complete all tests, including around 3 seconds for suite startup/teardown and average 0.38 second per test.

Under the hood of the Testing Infrastructure

Describe how we wait for a particular string on the UART. Some pointers into the robot files as well as any relevant documentation from Renode.

A test failure is the absence of a specific string on the UART so the test will wait for a specific timeout period (configured in the .robot) file before failing.

• What this means in practice is that a failing test will take longer to finish than a test that passes.

• If needed, an optimization on this would be to have a specific failure message as well so that both success and failure can be detected quickly.

Running a non-test Binary with Renode

Renode can also be used to run and debug binaries interactively. For example, to debug kernel_addr_test on Bluepill platform, run Renode:

tensorflow/lite/micro/tools/make/downloads/renode/renode

and issue following commands:

# Create platform
include @tensorflow/lite/micro/testing/bluepill_nontest.resc
# Load ELF file
sysbus LoadELF @tensorflow/lite/micro/tools/make/gen/bluepill_cortex-m3_default/bin/keyword_benchmark
# Start simulation
start

# To run again:
Clear
include @tensorflow/lite/micro/testing/bluepill_nontest.resc
sysbus LoadELF @tensorflow/lite/micro/tools/make/gen/bluepill_cortex-m3_default/bin/keyword_benchmark
start

To make repeat runs a bit easier, you can put all the commands into a single line (up arrow will show the last command in the Renode terminal):

Clear; include @tensorflow/lite/micro/testing/bluepill_nontest.resc; sysbus LoadELF @tensorflow/lite/micro/tools/make/gen/bluepill_cortex-m3_default/bin/keyword_benchmark; start

You can also connect GDB to the simulation. To do that, start the GDB server in Renode before issuing the start command:

machine StartGdbServer 3333

Than you can connect from GDB with:

target remote localhost:3333

For further reference please see the Renode documentation.

Useful External Links for Renode and Robot Documentation

• Testing with Renode

• Robot Testing Framework on Github. For someone new to the Robot Framework, the documentation can be a bit hard to navigate, so here are some links that are relevant to the use of the Robot Framework with Renode for TFLM:

  • Creating Test Data section of the user guide.

  • Renode-specific additions to the Robot test description format are in the RobotFrameworkEngine directory. For example,

    • Start Emulation
    • Wait For Line On Uart is where Wait For Line On Uart is defined.

  • Some documentation for all the Standard Libraries that define commands such as:

    • Remove File
    • List Files In Directory