Add user preference for GPU heap size limit

Should be set automatically according to memory needs, see #82

brian2cuda/device.py

@@ -49,6 +49,17 @@
  ''',
  ),
 
+ gpu_heap_size = BrianPreference(
+ docs='''
+ Size of the heap (in MB) used by malloc() and free() device system calls, which
+ are used in the `cudaVector` implementation. `cudaVectors` are used to
+ dynamically allocate device memory for `Spikemonitors` and the synapse
+ queues in the `CudaSpikeQueue` implementation for networks with
+ heterogeneously distributed delays.
+ ''',
+ validator=lambda v: isinstance(v, int) and v >= 0,
+ default=128),
+
  curand_float_type=BrianPreference(
  docs='''
  Floating point type of generated random numbers (float/double).
@@ -373,7 +384,8 @@ def generate_main_source(self, writer, main_includes):
  code_objects=self.code_objects.values(),
  report_func=self.report_func,
  dt=float(defaultclock.dt),
- additional_headers=main_includes
+ additional_headers=main_includes,
+ gpu_heap_size=prefs['devices.cuda_standalone.gpu_heap_size']
  )
  writer.write('main.cu', main_tmp)
 

brian2cuda/templates/main.cu

@@ -28,7 +28,7 @@ int main(int argc, char **argv)
 
  cudaDeviceProp props;
  cudaGetDeviceProperties(&props, 0);
- size_t limit = 128 * 1024 * 1024;
+ size_t limit = {{gpu_heap_size}} * 1024 * 1024;
  cudaDeviceSetLimit(cudaLimitMallocHeapSize, limit);
  cudaDeviceSynchronize();