Bifrst Visualizing and Checking Behavior of Embedded Systems across - - PowerPoint PPT Presentation

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Bifrst Visualizing and Checking Behavior of Embedded Systems across - - PowerPoint PPT Presentation

Aug 31, 2022 542 likes •1.17k views

Bifrst Visualizing and Checking Behavior of Embedded Systems across Hardware and Software Will McGrath wmcgrath@stanford.edu Jeremy Warner jeremy.warner@berkeley.edu e M bedded G ateway C loud [MGC] embedded gateway cloud 2 e M

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Bifröst

Visualizing and Checking Behavior

  • f Embedded Systems across

Hardware and Software

Will McGrath – wmcgrath@stanford.edu Jeremy Warner – jeremy.warner@berkeley.edu

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eMbedded Gateway Cloud [MGC]

embedded gateway cloud

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eMbedded Gateway Cloud [MGC]

embedded gateway cloud

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Program logic bug?

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Program logic bug? Protocol error?

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Program logic bug? Protocol error? Wiring issue?

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Program logic bug? Protocol error? Peripheral not configured? Wiring issue?

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Program logic bug? Protocol error? Peripheral not configured? Sensor data out of range? Wiring issue?

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Program logic bug? Protocol error? Peripheral not configured? Sensor data out of range? Wiring issue? Defective part?

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Toast Board

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Measures analog voltages at all breadboard rows Compares measured results to intended circuit to identify errors No embedded software support

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Existing Embedded Debugging Techniques

  • Multimeter
  • Point to point
  • Obscures rapid changes
  • Oscilloscope/Logic Analyzer
  • Fast, but expensive
  • Nontrivial configuration
  • Print Debugging
  • Easy, but weak time information
  • GDB
  • Powerful, but not always available
  • Complex configuration
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In contrast with prior work which has focused on providing tools only for debugging software or circuits, we directly address the interconnected nature of embedded systems projects.

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We believe that giving developers insight into how hardware and software interact in a richly-linked environment will enable more efficient debugging of embedded systems.

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Hardware Software

Sensors Actuators

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Bifröst

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Trace

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Bifröst: IDE Overview

Digital Signals Analog Signals Variable Values Code line at current time User Program Time-linked console

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Analysis Instrumentation Capture

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Instrumentation

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Hardware Instrumentation: Digital signals Analog signals Software Instrumentation: Line numbers Variable values

Analysis Capture

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Hardware Instrumentation: Digital signals Analog signals Software Instrumentation: Line numbers Variable values Record with Logic Analyzer

Analysis Instrumentation Capture

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Hardware Instrumentation: Digital signals Analog signals Software Instrumentation: Line numbers Variable values

Automatic & User Authored Checks

Signals Record with Logic Analyzer

Analysis Instrumentation Capture

Linked Visualization

Code Console

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Bifröst: usage example

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Bifröst: configuration

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Bifröst: blinking LED

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Bifröst: recording data

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Bifröst: variable tracing

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Bifröst: trace ⇔ code linkage

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Bifröst: code-based navigation

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Bifröst: console-based navigation

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Data Capture

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Capture: example

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Backend

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Capture: setup

Program Code

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Backend

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Capture: setup

Configuration Program Code Instrumented Code

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Backend

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Debugging information: code lines + function info

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Capture: execution

Backend

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Trace (w/ debug info) + decoded protocols Debugging information: code lines + function info

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Capture: execution

Backend

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Trace (w/ debug info) + decoded protocols Trace + Debug + Protocol Debugging information: code lines + function info

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Capture: execution

Backend

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incrementally step, record, and visualize

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Capture: inspection

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Code Instrumentation

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Code Instrumentation

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Core Library Instrumentation

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Checks

automatically inferred user-parameterized

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Checks: automatically inferred

“Writes should generate activity on a pin”

“Communication protocols adherence”

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Checks: user-parameterized

"when D1 rises expect line 11 in 100 ms"

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Checks: user-parameterized

"when D1 rises expect line 11 in 100 ms"

pin

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Checks: user-parameterized

"when D1 rises expect line 11 in 100 ms"

event pin

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Checks: user-parameterized

"when D1 rises expect line 11 in 100 ms"

source code pin event

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Checks: user-parameterized

"when D1 rises expect line 11 in 100 ms"

timing pin event source code

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“When D1 rises, expect Line 17 in 20 ms”

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Checks: user-parameterized

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“When D1 rises, expect Line 17 in 20 ms”

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Checks: user-parameterized

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“When D1 rises, expect Line 17 in 20 ms”

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Checks: user-parameterized

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How effectively does Bifröst aid embedded debugging?

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Evaluation

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Evaluation: issues

Users identified issues such as: pin misconfiguration thresholding issues switch bouncing timing issues

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Evaluation: strategies

Users identified these issues using: variable/signal data comparison code statement execution monitoring automatic and user-inferred checks

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Limitations

performance: instrumentation overhead (full speed to under 10x)

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scope:

  • nly instruments user code

and Arduino core functions

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Future Work

  • Support for continuous capture
  • Support for multiple devices
  • Checking & visualizing networked behavior
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Thanks!

With: Daniel Drew, Mitchell Karchemsky, Majeed Kazemitabaar, David Mellis, and Björn Hartmann

Will McGrath – wmcgrath@stanford.edu Jeremy Warner – jeremy.warner@berkeley.edu