I have an application which runs an edge-impulse model on an ESP32-S2 (IDF-version v5.0-rc1). I expect that this would also work on an ESP32-S3-WROOM-1 N8R8, but it doesn’t. (completely the same application)
In an attempt to mitigate this, I upgraded to the latest ESP-IDF v5.1 and downloaded the C++ library again from the edge impulse website, but the same error occurs.
The error I get is a corrupted heap when calling “run_classifier()”. Not always, but most of the time…
I (5263) analyser: Trying to take mutex for InferencingTask...
I (5683) analyser: Running classifier...
I (5683) analyser: heap integrety 1
I (5683) analyser: FreeHeapSize: 159276
I (5693) analyser: Bytes free in stack: 5580
I (6043) analyser: Inference results off/on: 1.00/0.00
I (6043) analyser: Entering InferencingTask FOR-loop...
I (6043) analyser: Trying to take mutex for InferencingTask...
I (6053) analyser: Running classifier...
I (6053) analyser: heap integrety 1
I (6063) analyser: FreeHeapSize: 159012
I (6063) analyser: Bytes free in stack: 5372
CORRUPT HEAP: Bad head at 0x3fcd1954. Expected 0xabba1234 got 0x0018fff3
assert failed: multi_heap_free multi_heap_poisoning.c:276 (head != NULL)
Is this a known issue?
Any pointers/ideas are very welcome 
Some details:
- ESP-IDF V5.1
- C++ library implementation
- Interference is running in a FreeRTOS task (as it is with the ESP32-S2)
I had following section in my CMakeList:
if(NOT CMAKE_BUILD_EARLY_EXPANSION)
add_definitions(-DEI_CLASSIFIER_TFLITE_ENABLE_ESP_NN=1) # enables ESP-NN optimizations by Espressif
endif()
Replacing this by:
if(NOT CMAKE_BUILD_EARLY_EXPANSION)
add_definitions(-DEI_CLASSIFIER_TFLITE_ENABLE_ESP_NN=0)
endif()
Fixed the issue, not completely sure why though…
The original post shows heap problems at runtime so the program is consuming to much RAM and crashes. Setting -DEI_CLASSIFIER_TFLITE_ENABLE_ESP_NN=0 forces the compiler to include generic NN optimizations that appear to be smaller in code size than when setting -DEI_CLASSIFIER_TFLITE_ENABLE_ESP_NN=1.
You can try these commands to see what is happening on the heap:
- ESP.getFreeHeap()
- ESP.getMinFreeHeap()
- ESP.getHeapSize()
- ESP.getMaxAllocHeap()
The ESP object is documented here.
Hi MMarcial,
Thank you for your reply. This is also something that came to mind and I tried to expand the memory allocated for the FreeRTOS task multiple times, but nothing changed.
I’ve also added logging before calling the crashing function (which is config->model_reset), but it always indicated enough free heap in my opinion, for example:
Heap integrety 1
FreeHeapSize: 142416
CORRUPT HEAP: Bad head at 0x3fcd3c80. Expected 0xabba1234 got 0xfffeffab
If it was a RAM issue, shouldn’t the same code on the ESP32-S2 (which has less RAM) also crash?
A big difference between ESP32-S2 and ESP32-S3 is that the ESP32-S2 is single core and the ESP32-S3 is dual core. But I would suspect that if I pin the task to a single core, this shouldn’t matter (but I’m no expert here).