Pinebook pro will not run a long stress test of OpenCL

Code:
// Example code is based on:
// * https://github.com/ctuning/ck-math/tree/master/program/acl-sgemm-opencl-example
//
// #ifndef ARM_COMPUTE_CL /* Needed by Utils.cpp to handle OpenCL exceptions properly */
// #error "This example needs to be built with -DARM_COMPUTE_CL"
// #endif /* ARM_COMPUTE_CL */

#include <arm_compute/core/Types.h>
#include <arm_compute/core/Helpers.h>
#include <arm_compute/core/ITensor.h>
#include "arm_compute/core/CL/CLKernelLibrary.h"

#include <arm_compute/runtime/Tensor.h>
#include "arm_compute/runtime/CL/CLFunctions.h"
#include "arm_compute/runtime/CL/CLScheduler.h"

#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>

#include <cctype>
#include <cerrno>
#include <iomanip>
#include <string>
#include <sys/time.h>

using namespace arm_compute;

// (MM, MN, MK) can be override from compiler options
#ifndef MM
#define MM 512
#endif
#ifndef MN
#define MN 512
#endif
#ifndef MK
#define MK 512
#endif

int main(void)
{
  long num_repetitions=1;
  struct timeval before, after;

  unsigned int m=MM;
  unsigned int n=MN;
  unsigned int k=MK;

  if (getenv("NUM_REPETITIONS")!=NULL) num_repetitions=atol(getenv("NUM_REPETITIONS"));
  if (getenv("MM")!=NULL) m=atol(getenv("MM"));
  if (getenv("MN")!=NULL) n=atol(getenv("MN"));
  if (getenv("MK")!=NULL) k=atol(getenv("MK"));
  printf("NUM_REPETITIONS = %lu\n", num_repetitions);
  printf("m = %u\n", m);
  printf("n = %u\n", n);
  printf("k = %u\n", k);

  TensorShape AShape(k,m);
  TensorShape BShape(n,k);
  TensorShape OShape(n,m);

  CLTensor ATensor;
  CLTensor BTensor;
  CLTensor OTensor;
  CLScheduler::get().default_init();

  ATensor.allocator()->init(TensorInfo(AShape,Format::F32));
  BTensor.allocator()->init(TensorInfo(BShape,Format::F32));
  OTensor.allocator()->init(TensorInfo(OShape,Format::F32));

  CLGEMM gemm;

  gemm.configure(&ATensor, &BTensor, NULL, &OTensor, 2.0f, 2.0f);

  ATensor.allocator()->allocate();
  BTensor.allocator()->allocate();
  OTensor.allocator()->allocate();

  gettimeofday(&before, NULL);
  for(int r = 0; r < num_repetitions; ++r) {
    gemm.run();
    CLScheduler::get().sync();
  }
  gettimeofday(&after, NULL);
  double total_time = (after.tv_sec - before.tv_sec) + 1e-6*(after.tv_usec - before.tv_usec);
  
  double flops = 2.0*m*n*k;
  double gflops = 1e-9 * flops;
  double avg_time = total_time / num_repetitions;
  double avg_gflops_per_sec = gflops / avg_time;

  printf("M = %u\nN = %u\nK = %u\n", m, n, k);
  printf("TIME_TOTAL = %lf\n", total_time);
  printf("TIME_AVG = %lf\n", avg_time);
  printf("GFLOPS_AVG = %lf\n", avg_gflops_per_sec);

  printf("------------- CLBLAST-STYLE_OUTPUT\n");
  printf("m = %u\nn = %u\nk = %u\n", m, n, k);
  printf("ms_1 = %lf\n", avg_time*1000);
  printf("GFLOPS_1 = %lf\n", avg_gflops_per_sec);

  return 0;
}