Getting Started

To use Skyline in your project, you need to first write an entry point file, which is a regular Python file that describes how your model is created and trained. See the Entry Point section for more information.

Once your entry point file is ready, navigate to your project's root directory and run:

skyline interactive path/to/entry/point/file

Then, open up Atom, execute the Skyline:Toggle command in the command palette (Ctrl-Shift-P on Ubuntu, ⌘-Shift-P on macOS), and hit the "Connect" button that appears on the right.

To shutdown Skyline, just execute the Skyline:Toggle command again in the command palette. You can shutdown the interactive profiling session on the command line by hitting Ctrl-C in your terminal.

You can also toggle Skyline using the Atom menus: Packages > Skyline > Show/Hide Skyline.

Virtual Environments

To analyze your model, Skyline will actually run your code. This means that when you invoke skyline interactive, you need to make sure that your shell has the proper environments activated (if needed). For example if you use virtualenv to manage your model's dependencies, you need to activate your virtualenv before starting Skyline.

Usage Statistics: Skyline collects usage statistics in order to help us make improvements to the tool. If you do not want Skyline to collect usage statistics, you can disable this functionality through Skyline's package settings in Atom (Atom > Settings/Preferences > Packages > Skyline > Settings).


To use Skyline, all of the code that you want to profile interactively must be stored under one common directory. Generally, this just means you need to keep your own source code under one common directory. Skyline considers all the files inside this common directory to be part of a project, and calls this common directory your project's root directory.

When starting a Skyline interactive profiling session, you must invoke skyline interactive <entry point> inside your project's root directory.

Entry Point

Skyline uses an entry point file to learn how to create and train your model. An entry point file is a regular Python file that contains three top-level functions:

  • skyline_model_provider
  • skyline_input_provider
  • skyline_iteration_provider

These three functions are called providers and must be defined with specific signatures. The easiest way to understand how to write the providers is to read through an example.


Suppose that your project code is kept under a my_project directory:


and your model is defined in
import torch.nn as nn
class Model(nn.Module):
def __init__(self):
self.conv = nn.Conv2d(in_channels=3, out_channels=6, kernel_size=3)
self.linear = nn.Linear(in_features=387096, out_features=10)
def forward(self, input):
out = self.conv(input)
return self.linear(out.view(-1, 387096))

One way to write the entry point file would be:
import torch
import torch.nn as nn
from my_project.model import Model
class ModelWithLoss(nn.Module):
def __init__(self):
self.model = Model()
self.loss_fn = nn.CrossEntropyLoss()
def forward(self, input, target):
output = self.model(input)
return self.loss_fn(output, target)
def skyline_model_provider():
# Return a GPU-based instance of our model (that returns a loss)
return ModelWithLoss().cuda()
def skyline_input_provider(batch_size=32):
# Return GPU-based inputs for our model
return (
torch.randn((batch_size, 3, 256, 256)).cuda(),
torch.randint(low=0, high=9, size=(batch_size,)).cuda(),
def skyline_iteration_provider(model):
# Return a function that executes one training iteration
optimizer = torch.optim.SGD(model.parameters(), lr=1e-3)
def iteration(*inputs):
out = model(*inputs)
return iteration

One important thing to highlight is our use of a wrapper ModelWithLoss module. Skyline only provides breakdowns for operations that run inside the module returned by the model provider. We included the loss function in this wrapper module to have Skyline include it in the breakdown. We could have also placed the loss function call in the iteration function.

You can place these provider functions either in a new file or directly in Whichever file contains the providers will be your project's entry point file. In this example, we defined the providers in a separate file called inside my_project.

Suppose that my_project is in your home directory. To launch Skyline you would run (in your shell):

cd ~/my_project
skyline interactive

Skyline will then start a profiling session and will launch Atom. To start profiling, hit the Connect button that appears in the sidebar.