JAX: Difference between revisions

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[https://github.com/google/jax JAX] is a framework for program transformation, esp. for automatic differentiation and machine learning. It's available on Nix/NixOS in the <code>python3Packages.{jax, jaxlib}</code> packages.
[https://github.com/google/jax JAX] is a framework for program transformation, esp. for automatic differentiation and machine learning. It's available on Nix/NixOS in the <code>python3Packages.{jax, jaxlib, jaxlibWithCuda}</code> packages.
 
'''Cache''': Using the [https://app.cachix.org/cache/cuda-maintainers#pull cuda-maintainers cache] is recommended! It will save you valuable time and electrons. Getting set up should be as simple as <code>cachix use cuda-maintainers</code>. See the [[CUDA]] wiki page for more info.


NOTE: JAX requires Python 3.9, the current version of <code>python3</code> in nixpkgs (as of 9/4/2021). JAX is currently only packaged for x86_64-linux (send a PR for your platform!).  
NOTE: JAX requires Python 3.9, the current version of <code>python3</code> in nixpkgs (as of 9/4/2021). JAX is currently only packaged for x86_64-linux (send a PR for your platform!).  
NOTE: JAX has not yet landed in nixpkgs master (see https://github.com/NixOS/nixpkgs/pull/134894). However, it is available via a fork: https://github.com/samuela/nixpkgs/tree/scratch.


== Example shell.nix, CPU only ==
== Example shell.nix, CPU only ==
<syntaxHighlight lang=nix>
<syntaxHighlight lang=nix>
let
let
   # Fork with jax/jaxlib. See https://github.com/NixOS/nixpkgs/pull/134894.
   # Last updated 01/31/2022. Check status.nixos.org for updates.
   pkgs = import (fetchTarball("https://github.com/samuela/nixpkgs/archive/dfc52fafe0cb7f574493e0e7c44c57200dd1a0fe.tar.gz")) {};
   pkgs = import (fetchTarball("https://github.com/NixOS/nixpkgs/archive/376934f4b7ca6910b243be5fabcf3f4228043725.tar.gz")) {};
in pkgs.mkShell {
in pkgs.mkShell {
   buildInputs = with pkgs; [
   buildInputs = with pkgs; [
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     python3Packages.jaxlib
     python3Packages.jaxlib
   ];
   ];
  # See https://github.com/google/jax/issues/5723#issuecomment-913038780
  XLA_FLAGS = "--xla_gpu_force_compilation_parallelism=1";
}
}
</syntaxHighlight>
</syntaxHighlight>
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hardware.opengl.enable = true;
hardware.opengl.enable = true;
</syntaxHighlight>
</syntaxHighlight>
Then you can use the jaxlib package by setting the <code>cudaSupport</code> parameter:
Then you can use the <code>jaxlibWithCuda</code> package (equivalent to setting the <code>cudaSupport</code> parameter):
<syntaxHighlight lang=nix>
<syntaxHighlight lang=nix>
let
let
   # Fork with jax/jaxlib. See https://github.com/NixOS/nixpkgs/pull/134894.
   # Last updated 01/31/2022. Check status.nixos.org for updates.
   pkgs = import (fetchTarball("https://github.com/samuela/nixpkgs/archive/dfc52fafe0cb7f574493e0e7c44c57200dd1a0fe.tar.gz")) {};
   pkgs = import (fetchTarball("https://github.com/NixOS/nixpkgs/archive/376934f4b7ca6910b243be5fabcf3f4228043725.tar.gz")) {};
in pkgs.mkShell {
in pkgs.mkShell {
   buildInputs = with pkgs; [
   buildInputs = with pkgs; [
     python3
     python3
     python3Packages.jax
     python3Packages.jax
     (python3Packages.jaxlib.override { cudaSupport = true; })
     python3Packages.jaxlibWithCuda
   ];
   ];
  # See https://github.com/google/jax/issues/5723#issuecomment-913038780
  XLA_FLAGS = "--xla_gpu_force_compilation_parallelism=1";
}
}
</syntaxHighlight>
</syntaxHighlight>
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It should print either "cpu", "gpu", or "tpu".
It should print either "cpu", "gpu", or "tpu".
Note that hydra may not cache <code>jaxlibWithCuda</code> builds on cache.nixos.org since CUDA is "unfree." @samuela publishes builds on a public cachix [https://app.cachix.org/cache/ploop#pull ploop] cache. These are periodically built and pushed from [https://github.com/samuela/nixpkgs-upkeep/ nixpkgs-upkeep].
== FAQ ==
=== How do I package JAX libraries? ===
Never ever ever put <code>jaxlib</code> in <code>propagatedBuildInputs</code>. However, it may live happily in <code>buildInputs</code> or <code>checkInputs</code>. See https://github.com/NixOS/nixpkgs/pull/156808 for context.
=== RuntimeError: Unknown: no kernel image is available for execution on the device ===
This usually indicates that you have a driver version that is too old for the CUDA toolkit version the package is built with. The easiest fix is to set the environment variable <code>XLA_FLAGS="--xla_gpu_force_compilation_parallelism=1"</code>. Also consider upgrading your CUDA driver.
See https://github.com/google/jax/issues/5723#issuecomment-913038780.
[[Category:Applications]]

Latest revision as of 19:27, 31 March 2022

JAX is a framework for program transformation, esp. for automatic differentiation and machine learning. It's available on Nix/NixOS in the python3Packages.{jax, jaxlib, jaxlibWithCuda} packages.

Cache: Using the cuda-maintainers cache is recommended! It will save you valuable time and electrons. Getting set up should be as simple as cachix use cuda-maintainers. See the CUDA wiki page for more info.

NOTE: JAX requires Python 3.9, the current version of python3 in nixpkgs (as of 9/4/2021). JAX is currently only packaged for x86_64-linux (send a PR for your platform!).

Example shell.nix, CPU only

let
  # Last updated 01/31/2022. Check status.nixos.org for updates.
  pkgs = import (fetchTarball("https://github.com/NixOS/nixpkgs/archive/376934f4b7ca6910b243be5fabcf3f4228043725.tar.gz")) {};
in pkgs.mkShell {
  buildInputs = with pkgs; [
    python3
    python3Packages.jax
    python3Packages.jaxlib
  ];
}

Example shell.nix with GPU support

JAX defers execution to the jaxlib library for execution. In order to use GPU support you'll need a NVIDIA GPU and OpenGL. In your /etc/nixos/configuration.nix:

# NVIDIA drivers are unfree
nixpkgs.config.allowUnfree = true;
services.xserver.videoDrivers = [ "nvidia" ];
hardware.opengl.enable = true;

Then you can use the jaxlibWithCuda package (equivalent to setting the cudaSupport parameter):

let
  # Last updated 01/31/2022. Check status.nixos.org for updates.
  pkgs = import (fetchTarball("https://github.com/NixOS/nixpkgs/archive/376934f4b7ca6910b243be5fabcf3f4228043725.tar.gz")) {};
in pkgs.mkShell {
  buildInputs = with pkgs; [
    python3
    python3Packages.jax
    python3Packages.jaxlibWithCuda
  ];
}

You can test that JAX is using the GPU as intended with

python -c "from jax.lib import xla_bridge; print(xla_bridge.get_backend().platform)"

It should print either "cpu", "gpu", or "tpu".

Note that hydra may not cache jaxlibWithCuda builds on cache.nixos.org since CUDA is "unfree." @samuela publishes builds on a public cachix ploop cache. These are periodically built and pushed from nixpkgs-upkeep.

FAQ

How do I package JAX libraries?

Never ever ever put jaxlib in propagatedBuildInputs. However, it may live happily in buildInputs or checkInputs. See https://github.com/NixOS/nixpkgs/pull/156808 for context.

RuntimeError: Unknown: no kernel image is available for execution on the device

This usually indicates that you have a driver version that is too old for the CUDA toolkit version the package is built with. The easiest fix is to set the environment variable XLA_FLAGS="--xla_gpu_force_compilation_parallelism=1". Also consider upgrading your CUDA driver.

See https://github.com/google/jax/issues/5723#issuecomment-913038780.