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5 tips for fast debugging of deployed IoT Devices


Johan-Kraft, CEO of Percepio outlines five best practices to reduce development risk, find out about bugs before your customers do and get the detailed information your developers need for efficient, continuous software improvement across deployed IoT devices


Feedback on real-world IoT device performance enables improvement of key performance metrics and the overall user experience. Most developers want to know about


runtime errors and warnings, which could arise because of software bugs or even hardware glitches that result in unexpected return values from the driver code. Maybe you also want a proactive warning when the stack usage of a task is close to the limit. But there are much broader


T


he real test of IoT devices comes after shipping, when thousands of


end users start using your product, sometimes in unexpected and untested ways. No software is entirely bug free, so some users will run into those remaining bugs. The question is how many and what you do about it.


1. PREPARE TO DEAL WITH BUGS Even if your product has been tested thoroughly and no more issues are found, chances are many more bugs remain. According to academic research, between 50-100 bugs are introduced per thousand lines of shipped code and about 5% remain in deployment. While some bugs are harmless, about 20% are major defects. Assuming your project has 50,000 lines of code, then 25-50 major defects likely remain in the product shipped to customers. These bugs are often elusive issues


that only show up under certain circumstances. Otherwise, the bugs would not have been missed by the testing. Customer support might receive complaints and returns, but it is not always clear whether the cause is a software issue, a hardware issue or user error. Make sure your embedded software


provides appropriate diagnostic information in case of any runtime errors or warnings. This can be achieved


20 APRIL 2021 | ELECTRONICS


by logging diagnostic messages about the software behaviour to a circular buffer in RAM. When an issue is encountered in the code, the most recent diagnostic data can be copied to non- volatile memory, including specific information about the issue and the events that led to the problem.


2. PROVIDE AUTOMATIC ALERTS By receiving automatic alerts and diagnostics from the devices themselves with the Percepio DevAlert device monitoring solution, developers can begin analysing the problem within seconds of the very first occurrence. During system testing, developers can


be notified immediately about issues and get detailed diagnostics, without relying on the tester to provide the exact circumstances. This approach also works for system


testing of general embedded software without cloud connectivity. The alerts and diagnostic data can be uploaded to a local computer that forwards the data to a central monitoring service. Secure IoT connectivity enables


diagnostic alerts from the field. This provides real-world feedback from IoT devices and enables rapid, continuous improvement of the device software.


3. MONITOR KEY PERFORMANCE METRICS


Johan-Kraft, CEO of Percepio


applications for automatic alerts. A developer can define custom alert types that capture any condition your software can detect. Percepio DevAlert compares every alert


with earlier alerts from your entire device fleet and groups them into specific issues, shown on a dashboard. This provides a clear overview and avoids repeated notifications about the same issue. Any repetitions of previously detected issues are counted and shown in the dashboard, which allows for issue prioritisation.


4. USE VISUAL TRACE DIAGNOSTICS The diagnostic data may contain a detailed software trace, showing the exact sequence of software threads, API calls, state changes and interrupts. Analysis of such information is greatly facilitated by visual trace diagnostics. This provides both a visual timeline of the events and multiple visual overviews from different perspectives, so any anomalies stand out.


5. DEPLOY OVER-THE-AIR (OTA) UPDATES QUICKLY Software issues in deployment typically don’t affect all users at once, otherwise testing would have found them. With IoT device monitoring, you become aware of any remaining issue on the very first occurrence, before most of customers notice.


Percepio https://percepio.com/


/ ELECTRONICS


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