Time of 1 pruning iteration

Hi, 

How long should I expect one pruning iteration to take? I'm talking about one iteration in this loop: 
for layer_index, filter_index in prune_targets:
      model = prune_vgg16_conv_layer(model, layer_index, filter_index)

It takes just over a second for me per iteration, is this normal? Can I move this process to the GPU since it seems idle at this stage?