forked from mirrors/nixpkgs
240 lines
9.8 KiB
XML
240 lines
9.8 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-gpu-accel">
|
|
<title>GPU acceleration</title>
|
|
<para>
|
|
NixOS provides various APIs that benefit from GPU hardware
|
|
acceleration, such as VA-API and VDPAU for video playback; OpenGL
|
|
and Vulkan for 3D graphics; and OpenCL for general-purpose
|
|
computing. This chapter describes how to set up GPU hardware
|
|
acceleration (as far as this is not done automatically) and how to
|
|
verify that hardware acceleration is indeed used.
|
|
</para>
|
|
<para>
|
|
Most of the aforementioned APIs are agnostic with regards to which
|
|
display server is used. Consequently, these instructions should
|
|
apply both to the X Window System and Wayland compositors.
|
|
</para>
|
|
<section xml:id="sec-gpu-accel-opencl">
|
|
<title>OpenCL</title>
|
|
<para>
|
|
<link xlink:href="https://en.wikipedia.org/wiki/OpenCL">OpenCL</link>
|
|
is a general compute API. It is used by various applications such
|
|
as Blender and Darktable to accelerate certain operations.
|
|
</para>
|
|
<para>
|
|
OpenCL applications load drivers through the <emphasis>Installable
|
|
Client Driver</emphasis> (ICD) mechanism. In this mechanism, an
|
|
ICD file specifies the path to the OpenCL driver for a particular
|
|
GPU family. In NixOS, there are two ways to make ICD files visible
|
|
to the ICD loader. The first is through the
|
|
<literal>OCL_ICD_VENDORS</literal> environment variable. This
|
|
variable can contain a directory which is scanned by the ICL
|
|
loader for ICD files. For example:
|
|
</para>
|
|
<programlisting>
|
|
$ export \
|
|
OCL_ICD_VENDORS=`nix-build '<nixpkgs>' --no-out-link -A rocm-opencl-icd`/etc/OpenCL/vendors/
|
|
</programlisting>
|
|
<para>
|
|
The second mechanism is to add the OpenCL driver package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages" />. This links
|
|
the ICD file under <literal>/run/opengl-driver</literal>, where it
|
|
will be visible to the ICD loader.
|
|
</para>
|
|
<para>
|
|
The proper installation of OpenCL drivers can be verified through
|
|
the <literal>clinfo</literal> command of the clinfo package. This
|
|
command will report the number of hardware devices that is found
|
|
and give detailed information for each device:
|
|
</para>
|
|
<programlisting>
|
|
$ clinfo | head -n3
|
|
Number of platforms 1
|
|
Platform Name AMD Accelerated Parallel Processing
|
|
Platform Vendor Advanced Micro Devices, Inc.
|
|
</programlisting>
|
|
<section xml:id="sec-gpu-accel-opencl-amd">
|
|
<title>AMD</title>
|
|
<para>
|
|
Modern AMD
|
|
<link xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
|
|
Core Next</link> (GCN) GPUs are supported through the
|
|
rocm-opencl-icd package. Adding this package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages" /> enables
|
|
OpenCL support:
|
|
</para>
|
|
<programlisting language="bash">
|
|
hardware.opengl.extraPackages = [
|
|
rocm-opencl-icd
|
|
];
|
|
</programlisting>
|
|
</section>
|
|
<section xml:id="sec-gpu-accel-opencl-intel">
|
|
<title>Intel</title>
|
|
<para>
|
|
<link xlink:href="https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units#Gen8">Intel
|
|
Gen8 and later GPUs</link> are supported by the Intel NEO OpenCL
|
|
runtime that is provided by the intel-compute-runtime package.
|
|
For Gen7 GPUs, the deprecated Beignet runtime can be used, which
|
|
is provided by the beignet package. The proprietary Intel OpenCL
|
|
runtime, in the intel-ocl package, is an alternative for Gen7
|
|
GPUs.
|
|
</para>
|
|
<para>
|
|
The intel-compute-runtime, beignet, or intel-ocl package can be
|
|
added to <xref linkend="opt-hardware.opengl.extraPackages" /> to
|
|
enable OpenCL support. For example, for Gen8 and later GPUs, the
|
|
following configuration can be used:
|
|
</para>
|
|
<programlisting language="bash">
|
|
hardware.opengl.extraPackages = [
|
|
intel-compute-runtime
|
|
];
|
|
</programlisting>
|
|
</section>
|
|
</section>
|
|
<section xml:id="sec-gpu-accel-vulkan">
|
|
<title>Vulkan</title>
|
|
<para>
|
|
<link xlink:href="https://en.wikipedia.org/wiki/Vulkan_(API)">Vulkan</link>
|
|
is a graphics and compute API for GPUs. It is used directly by
|
|
games or indirectly though compatibility layers like
|
|
<link xlink:href="https://github.com/doitsujin/dxvk/wiki">DXVK</link>.
|
|
</para>
|
|
<para>
|
|
By default, if <xref linkend="opt-hardware.opengl.driSupport" />
|
|
is enabled, mesa is installed and provides Vulkan for supported
|
|
hardware.
|
|
</para>
|
|
<para>
|
|
Similar to OpenCL, Vulkan drivers are loaded through the
|
|
<emphasis>Installable Client Driver</emphasis> (ICD) mechanism.
|
|
ICD files for Vulkan are JSON files that specify the path to the
|
|
driver library and the supported Vulkan version. All successfully
|
|
loaded drivers are exposed to the application as different GPUs.
|
|
In NixOS, there are two ways to make ICD files visible to Vulkan
|
|
applications: an environment variable and a module option.
|
|
</para>
|
|
<para>
|
|
The first option is through the
|
|
<literal>VK_ICD_FILENAMES</literal> environment variable. This
|
|
variable can contain multiple JSON files, separated by
|
|
<literal>:</literal>. For example:
|
|
</para>
|
|
<programlisting>
|
|
$ export \
|
|
VK_ICD_FILENAMES=`nix-build '<nixpkgs>' --no-out-link -A amdvlk`/share/vulkan/icd.d/amd_icd64.json
|
|
</programlisting>
|
|
<para>
|
|
The second mechanism is to add the Vulkan driver package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages" />. This links
|
|
the ICD file under <literal>/run/opengl-driver</literal>, where it
|
|
will be visible to the ICD loader.
|
|
</para>
|
|
<para>
|
|
The proper installation of Vulkan drivers can be verified through
|
|
the <literal>vulkaninfo</literal> command of the vulkan-tools
|
|
package. This command will report the hardware devices and drivers
|
|
found, in this example output amdvlk and radv:
|
|
</para>
|
|
<programlisting>
|
|
$ vulkaninfo | grep GPU
|
|
GPU id : 0 (Unknown AMD GPU)
|
|
GPU id : 1 (AMD RADV NAVI10 (LLVM 9.0.1))
|
|
...
|
|
GPU0:
|
|
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
|
|
deviceName = Unknown AMD GPU
|
|
GPU1:
|
|
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
|
|
</programlisting>
|
|
<para>
|
|
A simple graphical application that uses Vulkan is
|
|
<literal>vkcube</literal> from the vulkan-tools package.
|
|
</para>
|
|
<section xml:id="sec-gpu-accel-vulkan-amd">
|
|
<title>AMD</title>
|
|
<para>
|
|
Modern AMD
|
|
<link xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
|
|
Core Next</link> (GCN) GPUs are supported through either radv,
|
|
which is part of mesa, or the amdvlk package. Adding the amdvlk
|
|
package to <xref linkend="opt-hardware.opengl.extraPackages" />
|
|
makes amdvlk the default driver and hides radv and lavapipe from
|
|
the device list. A specific driver can be forced as follows:
|
|
</para>
|
|
<programlisting language="bash">
|
|
hardware.opengl.extraPackages = [
|
|
pkgs.amdvlk
|
|
];
|
|
|
|
# To enable Vulkan support for 32-bit applications, also add:
|
|
hardware.opengl.extraPackages32 = [
|
|
pkgs.driversi686Linux.amdvlk
|
|
];
|
|
|
|
# Force radv
|
|
environment.variables.AMD_VULKAN_ICD = "RADV";
|
|
# Or
|
|
environment.variables.VK_ICD_FILENAMES =
|
|
"/run/opengl-driver/share/vulkan/icd.d/radeon_icd.x86_64.json";
|
|
</programlisting>
|
|
</section>
|
|
</section>
|
|
<section xml:id="sec-gpu-accel-common-issues">
|
|
<title>Common issues</title>
|
|
<section xml:id="sec-gpu-accel-common-issues-permissions">
|
|
<title>User permissions</title>
|
|
<para>
|
|
Except where noted explicitly, it should not be necessary to
|
|
adjust user permissions to use these acceleration APIs. In the
|
|
default configuration, GPU devices have world-read/write
|
|
permissions (<literal>/dev/dri/renderD*</literal>) or are tagged
|
|
as <literal>uaccess</literal>
|
|
(<literal>/dev/dri/card*</literal>). The access control lists of
|
|
devices with the <literal>uaccess</literal> tag will be updated
|
|
automatically when a user logs in through
|
|
<literal>systemd-logind</literal>. For example, if the user
|
|
<emphasis>jane</emphasis> is logged in, the access control list
|
|
should look as follows:
|
|
</para>
|
|
<programlisting>
|
|
$ getfacl /dev/dri/card0
|
|
# file: dev/dri/card0
|
|
# owner: root
|
|
# group: video
|
|
user::rw-
|
|
user:jane:rw-
|
|
group::rw-
|
|
mask::rw-
|
|
other::---
|
|
</programlisting>
|
|
<para>
|
|
If you disabled (this functionality of)
|
|
<literal>systemd-logind</literal>, you may need to add the user
|
|
to the <literal>video</literal> group and log in again.
|
|
</para>
|
|
</section>
|
|
<section xml:id="sec-gpu-accel-common-issues-mixing-nixpkgs">
|
|
<title>Mixing different versions of nixpkgs</title>
|
|
<para>
|
|
The <emphasis>Installable Client Driver</emphasis> (ICD)
|
|
mechanism used by OpenCL and Vulkan loads runtimes into its
|
|
address space using <literal>dlopen</literal>. Mixing an ICD
|
|
loader mechanism and runtimes from different version of nixpkgs
|
|
may not work. For example, if the ICD loader uses an older
|
|
version of glibc than the runtime, the runtime may not be
|
|
loadable due to missing symbols. Unfortunately, the loader will
|
|
generally be quiet about such issues.
|
|
</para>
|
|
<para>
|
|
If you suspect that you are running into library version
|
|
mismatches between an ICL loader and a runtime, you could run an
|
|
application with the <literal>LD_DEBUG</literal> variable set to
|
|
get more diagnostic information. For example, OpenCL can be
|
|
tested with <literal>LD_DEBUG=files clinfo</literal>, which
|
|
should report missing symbols.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
</chapter>
|