After playing with tensorflow example codes quite a bit, I think I am ready, and actually cannot wait to unleash the power of GPU. There are so many benchmarks here and there where people brag about how GPU kicks CPU’s ass when it comes to massive computation tasks. I threw a few hundred bucks into my first GPU purely to play top notch video games – Starcraft II back when it first came out, thanks to Blizzard entertainment. Using GPU for machine learning is purely a afterthought, looking back.

This weekend, I brought a GPU workstation back home. However, after being put off by my wife telling me that “I do not want you to make mess in our living room, you can not put anything on the table….”. The sad part, the workstation does not have wireless internet connection, and what is even worse, we only have ethernet connection right next to the router in the living room. Take all constraints into consideration, the only option left here is to leave the desktop as a remote server and access it through other devices (other computers within the same network).

Thank goodness, it was quite easy to set up any Ubuntu machine to be accessed through ssh. Actually, there is no need to set up remote desktop, since we can use the terminal for anything graphic related like web surfing. The only thing we need to do is set up the desktop as a server, people can ssh in, and for the Python related developer, we also need to set up the desktop as a jupyter notebook server where we are going to conduct our experiment.

As you can see in the end, we merely need to plug a power and ethernet cable to the desktop. The moment you power it on, you should be able to access the desktop via SSH and you can even power it off remotely by issuing comment “sudo shutdown”. Now you can work in your bed and never even come off your bed to shut it down!

Also, to make it slightly easier for consistency access, I suggest you log into the router to reserve an IP so that the desktop will not be assigned to a different IP every time it is reboot or what, due to the fact that DHCP is the default many default devices.

After that, you can SSH into your computer, conda install or pip install to set up the tensorflow CUDA development environment. However, it might still be a PITA to develop without any IDE, and in this case, I will be using jupyter notebook. Jupyter notebook does not handle multi-tenancy that well, say you have multiple people accessing the server at the same time. Jupyterhub is supposed to be the tool to ease that pain and the installation and set up are fairly easy. Since I will the only user within the network, I literally did nothing but ran the command “jupyterhub” and now we have a jupyter notebook running that you can simply enter the address “10.0.0.54:8000” on any laptop within the network (wifi, ethernet,..). And here is how it looks like on my MacBook Pro accessing that GPU desktop:

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For those curious mind, look at the slideshow above proving that I am running the Udacity fullyconnected notebook and it is actually running on top of a lovely GPU!

The source code is from here. Since the source code was coded to demonstrate the fundamentals of tensorflow which is not necessarily to run the code on GPU. There will not be any proof right out of box any step is actually using GPU (if available GPU and CPU coexist, tensorflow actually will prioritize GPU).

Here is a snippet of code where I want to highlight. tf.ConfigProto, device_count to be 0 will force the machine to use CPU which you can compare with when you have an time consuming task (the notebook was quite fast using either CPU or GPU).

config = tf.ConfigProto(
    log_device_placement=True, 
    device_count = {'GPU': 0}
)
graph = tf.Graph()
with graph.as_default():
 ...
with tf.Session(graph=graph, config=config) as session:
    tf.global_variables_initializer().run()
    ...
    _, l, predictions = session.run([optimizer, loss, train_prediction], feed_dict=feed_dict)
    ...

Also, log_device_placement set to be true will enable detailed logging about operations.

I think this is the end of this post. Nothing new, nothing ground breaking, but quite a fun to see everything got put together, right?