This is a primary source :) Something needs to handle those interrupts. Perhaps ...

This is a primary source :) Something needs to handle those interrupts. Perhaps this stack trace from the profiler may be enlightening as to what that thing is:

  810 -[AXPhoenixClassifier _handleAccelerometerData:withTimestamp:] 
  563 -[MLModel predictionFromFeatures:error:] 
  561 -[MLNeuralNetworkEngine predictionFromFeatures:options:error:] 
  542 _dispatch_lane_barrier_sync_invoke_and_complete 
  542 _dispatch_client_callout 
  541 __62-[MLNeuralNetworkEngine predictionFromFeatures:options:error:]_block_invoke 
  521 -[MLNeuralNetworkEngine evaluateInputs:options:error:] 
  519 -[MLNeuralNetworkEngine evaluateInputs:options:verifyInputs:error:] 
  491 _dispatch_lane_barrier_sync_invoke_and_complete 
  491 _dispatch_client_callout 
  491 __67-[MLNeuralNetworkEngine evaluateInputs:options:verifyInputs:error:]_block_invoke.195 
  491 -[MLNeuralNetworkEngine evaluateInputs:bufferIndex:options:error:] 
  363 -[MLNeuralNetworkEngine executePlan:error:] 
  359 espresso_plan_execute_sync 
  358 EspressoLight::espresso_plan::execute_sync() 
  351 EspressoLight::espresso_plan::dispatch_task_on_compute_batch(std::__1::shared_ptr<Espresso::abstract_batch> const&, std::__1::shared_ptr<EspressoLight::plan_task_t> const&) 
  296 Espresso::net::__forward(std::__1::shared_ptr<Espresso::abstract_batch> const&, int, int) 
  294 Espresso::net_compiler_segment_based::__forward(std::__1::shared_ptr<Espresso::abstract_batch> const&) 
  290 Espresso::ANERuntimeEngine::compiler::__forward_segment(std::__1::shared_ptr<Espresso::abstract_batch> const&, int, Espresso::net_compiler_segment_based::segment_t const&) 
  254 -[_ANEClient doEvaluateDirectWithModel:options:request:qos:error:] 
  247 -[_ANEProgramForEvaluation processRequest:model:qos:qIndex:modelStringID:options:error:] 
  221 H11ANEProgramProcessRequestDirect 
  214 H11ANE::H11ANEFrameReceiver::ProgramProcessRequest(H11ANE::H11ANEFrameReceiverRequest&, H11ANESharedEventsStruct*, bool) 
  201 H11ANE::H11ANEDevice::ANE_ProgramSendRequest(H11ANEProgramRequestArgsStruct*, unsigned int, bool, H11ANEReqCallbackDataStruct*) 
  200 IOConnectCallAsyncMethod 
  200 io_connect_async_method 
  199 mach_msg2_internal 
  199 mach_msg2_trap