Managing GPU dependencies
OverviewTeaching: 45 min
Exercises: 15 minQuestions
Which NVIDIA libraries are available via Conda?
What do you do when you need the NVIDIA CUDA Compiler (NVCC) for your project?Objectives
Show how to use Conda to manage key GPU dependencies for you next (data) science project.
Show how to identify which versions of CUDA packages are available via Conda.
Understand how to write a Conda environment file for a project with GPU dependencies.
Understand when you need the NVIDIA CUDA Compiler (NVCC) and how to handle this situation.
Getting familiar with NVIDIA CUDA libraries
Transitioning your (data) science projects from CPU to GPU can seem like a daunting task. In particular, there is quite a bit of unfamiliar additional software, such as NVIDIA CUDA Toolkit, NVIDIA Collective Communications Library (NCCL), and NVIDIA Deep Neural Network Library (cuDNN) to download and install.
If you go to the NVIDIA developer website you will find loads of documentation and instructions for how to install these libraries system wide. But then what do you do if you need different versions of these new libraries for different projects? You could install a bunch of different versions of NVIDIA CUDA Toolkit, NCCL, and cuDNN system wide and then use environment variables to control the “active” versions for each project but this is cumbersome and error prone. Fortunately there are better ways!
In this episode we are going to see how to manage project specific versions of the NVIDIA CUDA Toolkit, NCCL, and cuDNN using Conda.
Are NVIDIA libraries available via Conda?
Yep! The most important NVIDIA CUDA library that you will need is the NVIDIA CUDA Toolkit. The
NVIDIA CUDA Toolkit provides a development environment for creating high performance
GPU-accelerated applications. The toolkit includes GPU-accelerated libraries, debugging and
optimization tools and a runtime library. You can use the
conda search command to see what
versions of the NVIDIA CUDA Toolkit are available from the default channels.
$ conda search cudatoolkit Loading channels: done # Name Version Build Channel cudatoolkit 9.0 h13b8566_0 pkgs/main cudatoolkit 9.2 0 pkgs/main cudatoolkit 10.0.130 0 pkgs/main cudatoolkit 10.1.168 0 pkgs/main cudatoolkit 10.1.243 h6bb024c_0 pkgs/main cudatoolkit 10.2.89 hfd86e86_0 pkgs/main cudatoolkit 10.2.89 hfd86e86_1 pkgs/main
NVIDIA actually maintains their own Conda channel and the versions of CUDA Toolkit available from the default channels are the same as those you will find on the NVIDIA channel. If you are interested in confirming this you can run the command
$ conda search --channel nvidia cudatoolkit
and then compare the build numbers with those listed above from the default channels.
The CUDA Toolkit packages available from defaults do not include NVCC
An important limitation of the versions of the NVIDIA CUDA Toolkit that are available from the either the default or NVIDIA Conda channels is that they do not include the NVIDIA CUDA Compiler (NVCC).
What about cuDNN?
The NVIDIA CUDA Deep Neural Network library (cuDNN) is a GPU-accelerated library of primitives for deep neural networks. cuDNN provides highly tuned implementations for standard routines such as forward and backward convolution, pooling, normalization, and activation layers.
If you are interested in deep learning, then you will need to get your hands on cuDNN. Various versions of cuDNN are available from the default channels.
$ conda search cudnn Loading channels: done # Name Version Build Channel cudnn 7.0.5 cuda8.0_0 pkgs/main cudnn 7.1.2 cuda9.0_0 pkgs/main cudnn 7.1.3 cuda8.0_0 pkgs/main cudnn 7.2.1 cuda9.2_0 pkgs/main cudnn 7.3.1 cuda10.0_0 pkgs/main cudnn 7.3.1 cuda9.0_0 pkgs/main cudnn 7.3.1 cuda9.2_0 pkgs/main cudnn 7.6.0 cuda10.0_0 pkgs/main cudnn 7.6.0 cuda10.1_0 pkgs/main cudnn 7.6.0 cuda9.0_0 pkgs/main cudnn 7.6.0 cuda9.2_0 pkgs/main cudnn 7.6.4 cuda10.0_0 pkgs/main cudnn 7.6.4 cuda10.1_0 pkgs/main cudnn 7.6.4 cuda9.0_0 pkgs/main cudnn 7.6.4 cuda9.2_0 pkgs/main cudnn 7.6.5 cuda10.0_0 pkgs/main cudnn 7.6.5 cuda10.1_0 pkgs/main cudnn 7.6.5 cuda10.2_0 pkgs/main cudnn 7.6.5 cuda9.0_0 pkgs/main cudnn 7.6.5 cuda9.2_0 pkgs/main
What about NCCL?
If you are already accelerating your (data) science workflows with a GPU, then in the near future you will probably be interested in using more than one GPU. The NVIDIA Collective Communications Library (NCCL) implements multi-GPU and multi-node collective communication primitives that are performance optimized for NVIDIA GPUs.
There are some older versions of NCCL available from the default channels but these versions will not be useful (unless, perhaps, you are forced to use very old versions of TensorFlow or similar).
$ conda search nccl Loading channels: done # Name Version Build Channel nccl 1.3.5 cuda10.0_0 pkgs/main nccl 1.3.5 cuda9.0_0 pkgs/main nccl 1.3.5 cuda9.2_0 pkgs/main
Not to worry: Conda Forge to the rescue! Conda Forge is a
community-led collection of recipes, build infrastructure and distributions for the Conda package
manager. I always check the
conda-forge channel when I can’t find something I need available on
the default channels.
Which version of NCCL are available via Conda Forge?
Find out which versions of the NVIDIA Collective Communications Library (NCCL) are available via Conda Forge?
conda searchcommand with the
$ conda search --channel conda-forge nccl Loading channels: done # Name Version Build Channel nccl 1.3.5 cuda10.0_0 pkgs/main nccl 1.3.5 cuda9.0_0 pkgs/main nccl 1.3.5 cuda9.2_0 pkgs/main nccl 22.214.171.124 h51cf6c1_0 conda-forge nccl 126.96.36.199 h7cc98d6_0 conda-forge nccl 188.8.131.52 hc6a2c23_0 conda-forge nccl 184.108.40.206 hd6f8bf8_0 conda-forge nccl 220.127.116.11 h51cf6c1_0 conda-forge nccl 18.104.22.168 h7cc98d6_0 conda-forge nccl 22.214.171.124 hd6f8bf8_0 conda-forge nccl 126.96.36.199 h51cf6c1_0 conda-forge nccl 188.8.131.52 h51cf6c1_1 conda-forge nccl 184.108.40.206 h7cc98d6_0 conda-forge nccl 220.127.116.11 h7cc98d6_1 conda-forge nccl 18.104.22.168 hd6f8bf8_0 conda-forge nccl 22.214.171.124 hd6f8bf8_1 conda-forge nccl 126.96.36.199 h51cf6c1_0 conda-forge nccl 188.8.131.52 h7cc98d6_0 conda-forge nccl 184.108.40.206 hc6a2c23_0 conda-forge nccl 220.127.116.11 hd6f8bf8_0 conda-forge nccl 18.104.22.168 h51cf6c1_0 conda-forge nccl 22.214.171.124 h7cc98d6_0 conda-forge nccl 126.96.36.199 hc6a2c23_0 conda-forge nccl 188.8.131.52 hd6f8bf8_0 conda-forge nccl 184.108.40.206 h51cf6c1_0 conda-forge nccl 220.127.116.11 h7cc98d6_0 conda-forge nccl 18.104.22.168 hc6a2c23_0 conda-forge nccl 22.214.171.124 hd6f8bf8_0 conda-forge
Some example Conda environment files
Now that you know how to figure out which versions of the various NVIDIA CUDA libraries are available on which channels you are ready to write your environment.yml file. In this section I will provide some example Conda environment files for PyTorch, TensorFlow, and NVIDIA RAPIDS to help get you started on your next GPU data science project.
PyTorch is an open source machine learning library based on the Torch
library, used for applications such as computer vision and natural language processing. It is
primarily developed by Facebook’s AI Research lab. Conda is actually the
recommended way to install PyTorch. The official
PyTorch binary ships with NCCL and cuDNN so it is not necessary to include these libraries in
environment.yml file (unless some other package also needs these libraries!).
name: null channels: - pytorch - conda-forge - defaults dependencies: - cudatoolkit=10.1 - pip=20.0 - python=3.7 - pytorch=1.5 - torchvision=0.6
Check your channel priorities!
Also take note of the channel priorities: the official
pytorchchannel must be given priority over
conda-forgein order to insure that the official PyTorch binaries (the ones that include NCCL and cuDNN) will be installed (otherwise you will get some unofficial version of PyTorch available on
TensorFlow is a free, open-source software library for dataflow and
differentiable programming across a range of tasks. It is a symbolic math library, and is also used
for machine learning applications such as neural networks. There are lots of versions and builds of
TensorFlow available via Conda (the output of
conda search tensorflow is too long to share here!).
How do you decide which version is the “correct” version? How to make sure that you get a build that includes GPU support? At this point you have seen all the Conda “tricks” required to solve this one yourself!
environment.ymlfile for TensorFlow
In this exercise you will create a Conda environment for TensorFlow. Important CUDA dependencies of TensorFlow are the CUDA Toolkit, cuDNN, and CUPTI. Don’t forget that if you want to train on more than one GPU, then your environment will also need NCCL and an MPI implementation.
tensorflow-gpumeta-package to select the appropriate version and build of TensorFlow for your OS; use
mpi4pyto get a CUDA-aware OpenMPI build.
name: null channels: - conda-forge - defaults dependencies: - cudatoolkit=10.1 - cudnn=7.6 - cupti=10.1 - mpi4py=3.0 # installs cuda-aware openmpi - nccl=2.4 - pip=20.0 - python=3.7 - tensorflow-gpu=2.1 # installs tensorflow=2.1=gpu_py37h7a4bb67_0
NVIDIA RAPIDS (+BlazingSQL+Datashader)
As a final example let’s see how to get started with NVIDIA RAPIDS (and friends!). NVIDIA RAPIDS is a suite of open source software libraries and APIs gives you the ability to execute end-to-end data science and analytics pipelines entirely on GPUs (think Pandas + Scikit-learn but for GPUs instead of CPUs). In addition to RAPIDS we have also included BlazingSQL in this example environment file. BlazingSQL is an open-source SQL interface to extract-transform-load (ETL) massive datasets directly into GPU memory for analysis using NVIDIA RAPIDS. The environment also includes Datashader, a graphics pipeline system for creating meaningful representations of large datasets quickly and flexibly, that can be accelerated with GPUs. If you are going to do all of your data analysis on the GPU, then you might as well do your data visualization on the GPU too!
name: null channels: - blazingsql - rapidsai - nvidia - conda-forge - defaults dependencies: - blazingsql=0.13 - cudatoolkit=10.1 - datashader=0.10 - pip=20.0 - python=3.7 - rapids=0.13
What exactly is installed when you install NVIDIA RAPIDS?
Create an NVIDIA RAPIDS environment using the Conda environment file above. Use Conda commands to inspect the complete list of packages that have been installed. Do you recognize any of the packages?
Use the following commands to create the environment.
$ mkdir nvidia-rapids-project $ cd nvidia-rapids-project/ $ nano environment.yml # copy-paste the environment file contents $ conda env create --prefix ./env --file environment.yml
Use the following commands to activate the environment and list all the packages installed.
$ conda activate ./env $ conda list
But what if I need the NVIDIA CUDA Compiler?
Way up at the beginning of this episode I mention that the versions of the NVIDIA CUDA Toolkit available via the default channels did not include the NVIDIA CUDA Compiler (NVCC). However, if your data science project has dependencies that require compiling custom CUDA extensions then you will almost surely need the NVIDIA CUDA Compiler (NVCC).
How do you know that your project dependencies need NVCC? Most likely you will try the standard approaches above and Conda will fail to successfully create the environment and perhaps throw a bunch of compiler errors. Once you know that you need NVCC, there are a couple of ways to get the NVCC compiler installed.
First, try the
The cudatoolkit-dev package available from the conda-forge channel includes GPU-accelerated libraries, debugging and optimization tools, a C/C++ compiler and a runtime library. This package consists of a post-install script that downloads and installs the full CUDA toolkit (NVCC compiler and libraries, but not the exception of CUDA drivers).
While the cudatoolkit-dev packages available from conda-forge do include NVCC, I have had difficult getting these packages to consistently install properly.
- Some of the available builds require manual intervention to accept license agreements making these builds unsuitable for installing on remote systems (which is critical functionality).
- Some other builds seem to work on Ubuntu but not on other flavors of Linux such as CentOS.
- Other Conda packages that depend on CUDA will often install the cudatoolkit package even though everything included in this package will have already been installed via cudatoolkit-dev.
That said, it is always worth trying the
cudatoolkit-dev approach first. Maybe it will work for
your use case. Here is an example that uses NVCC installed via the cudatoolkit-dev package to
compile custom extensions from PyTorch Cluster, a
small extension library of highly optimized graph cluster algorithms for the use with
name: null channels: - pytorch - conda-forge - defaults dependencies: - cudatoolkit-dev=10.1 - cxx-compiler=1.0 - matplotlib=3.2 - networkx=2.4 - numba=0.48 - pandas=1.0 - pip=20.0 - pip: - -r file:requirements.txt - python=3.7 - pytorch=1.4 - scikit-image=0.16 - scikit-learn=0.22 - tensorboard=2.1 - torchvision=0.5
requirements.txt file referenced above contains PyTorch Cluster and related packages such as
PyTorch Geometric. Here is what that file looks
torch-scatter==2.0.* torch-sparse==0.6.* torch-spline-conv==1.2.* torch-cluster==1.5.* torch-geometric==1.4.* # make sure the following are re-compiled if environment is re-built --no-binary=torch-scatter --no-binary=torch-sparse --no-binary=torch-spline-conv --no-binary=torch-cluster --no-binary=torch-geometric
The use of the
--no-binary option here insures that the packages with custom extensions will be
re-built whenever the environment is re-built which helps increase the reproducibility of the
environment build process when porting from workstations to remote clusters that might have
…if that doesn’t work, then use the
The most robust approach to obtain NVCC and still use Conda to manage all the other dependencies
is to install the NVIDIA CUDA Toolkit on your system and then install a meta-package nvcc_linux-64
from conda-forge which configures your Conda environment to use the NVCC installed on your system
together with the other CUDA Toolkit components installed inside the Conda environment. While we
have found this approach to be more robust then relying on
cudatoolkit-dev, this approach is more
involved as it requires installing a
particular version of the NVIDIA CUDA Toolkit
on your system first.
In order to demonstrate how to use the
nvcc_linux-64 meta-package approach we will show how to
build a Conda environment for deep learning projects that use Horovod to enable distributed
training across multiple GPUs (either on the same node or spread across multiple nodes).
Horovod is an open-source distributed training framework for TensorFlow, Keras, PyTorch, and Apache MXNet. Originally developed by Uber for in-house use, Horovod was open sourced a couple of years ago and is now an official Linux Foundation AI (LFAI) project.
Let’s checkout the
environment.yml file. You can find this
environment.yml file on GitHub as a
part of a template repository to
help you get started with Horovod.
name: null channels: - pytorch - conda-forge - defaults dependencies: - bokeh=1.4 - cmake=3.16 # insures that Gloo library extensions will be built - cudnn=7.6 - cupti=10.1 - cxx-compiler=1.0 # insures C and C++ compilers are available - jupyterlab=1.2 - mpi4py=3.0 # installs cuda-aware openmpi - nccl=2.5 - nodejs=13 - nvcc_linux-64=10.1 # configures environment to be "cuda-aware" - pip=20.0 - pip: - mxnet-cu101mkl==1.6.* # MXNET is installed prior to horovod - -r file:requirements.txt - python=3.7 - pytorch=1.4 - tensorboard=2.1 - tensorflow-gpu=2.1 - torchvision=0.5
Take note of the channel priorities:
pytorch is given highest priority in order to insure that
the official PyTorch binary is installed (and not the binaries available on
are also a few things worth noting about the dependencies. Even though you have installed the
NVIDIA CUDA Toolkit manually you can still use Conda to manage the other required CUDA components
nccl (and the optional
- We use two meta-packages,
nvcc_linux-64, to make sure that suitable C, and C++ compilers are installed and that the resulting Conda environment is aware of the manually installed CUDA Toolkit.
- Horovod requires some controller library to coordinate work between the various Horovod processes.
Typically this will be some MPI implementation such as OpenMPI. However, rather than specifying
openmpipackage directly, opt for
mpi4pyConda package which will install a CUDA-aware build of OpenMPI (assuming it is supported by your hardware).
- Horovod also supports the Gloo collective communications library that can be used in place of MPI.
If you include
cmakein order to insure that the Horovod extensions for Gloo are built.
requirements.txt file is where all of the dependencies, including Horovod itself, are
listed for installation via
pip. In addition to Horovod, it is recommended to use
pip to install
JupyterLab extensions to enable GPU and CPU resource monitoring via
Tensorboard support via
jupyter-tensorboard. Note the use of the
--no-binary option at the end of the file. Including this option insures that Horovod will be
re-built whenever the Conda environment is re-built.
horovod==0.19.* jupyterlab-nvdashboard==0.2.* jupyter-tensorboard==0.2.* # make sure horovod is re-compiled if environment is re-built --no-binary=horovod
Creating the Conda environment
You can create the Conda environment in a sub-directory
env of your project directory by
running the following commands. By default Horovod will try and build extensions for all
detected frameworks. See the Horovod documentation on
for the details on additional environment variables that can be set prior to building Horovod.
export ENV_PREFIX=$PWD/env export HOROVOD_CUDA_HOME=$CUDA_HOME export HOROVOD_NCCL_HOME=$ENV_PREFIX export HOROVOD_GPU_OPERATIONS=NCCL conda env create --prefix $ENV_PREFIX --file environment.yml --force
Wrap complex Conda environment builds in a script!
In order to enhance reproducibility of your complex Conda build, I typically wrap commands into a shell script called
create-conda-env.sh. Running the shell script will set the Horovod build variables, create the Conda environment, activate the Conda environment, and build JupyterLab with any additional extensions as specified in a
#!/bin/bash --login set -e export ENV_PREFIX=$PWD/env export HOROVOD_CUDA_HOME=$CUDA_HOME export HOROVOD_NCCL_HOME=$ENV_PREFIX export HOROVOD_GPU_OPERATIONS=NCCL conda env create --prefix $ENV_PREFIX --file environment.yml --force conda activate $ENV_PREFIX . postBuild
You can put scripts inside a
bindirectory in my project root directory. The script should be run from the project root directory as follows.
We covered a lot of ground in this episode! We showed you how to use
conda search to see which
versions of the NVIDIA CUDA Toolkit and related libraries such as NCCL and cuDNN were available
via Conda. Then we walked you through example Conda environment files for several popular data
science frameworks that can use GPUs. We wrapped up with a discussion of two different approaches
for getting NVCC when your project requires compiler custom CUDA extensions. Hopefully these ideas
will help you make the jump from CPUs to GPUs on your next data science project!
Conda can be used to manage your key GPU dependencies.
conda searchto identify which version of CUDA libraries are available.
For most projects you will not need NVCC and can use the
cudatoolkitpackage from default channels.
If your project does need NVCC, try
nvcc_linux-64meta-package (requires separate NVIDIA CUDA Toolkit install).