263 lines
10 KiB
XML
263 lines
10 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
|
|
xmlns:xlink="http://www.w3.org/1999/xlink"
|
|
xmlns:xi="http://www.w3.org/2001/XInclude"
|
|
version="5.0"
|
|
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 <varname>OCL_ICD_VENDORS</varname>
|
|
environment variable. This variable can contain a directory which
|
|
is scanned by the ICL loader for ICD files. For example:
|
|
|
|
<screen><prompt>$</prompt> export \
|
|
OCL_ICD_VENDORS=`nix-build '<nixpkgs>' --no-out-link -A rocm-opencl-icd`/etc/OpenCL/vendors/</screen>
|
|
</para>
|
|
|
|
<para>
|
|
The second mechanism is to add the OpenCL driver package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages"/>. This links the
|
|
ICD file under <filename>/run/opengl-driver</filename>, where it will
|
|
be visible to the ICD loader.
|
|
</para>
|
|
|
|
<para>
|
|
The proper installation of OpenCL drivers can be verified through
|
|
the <command>clinfo</command> command of the <package>clinfo</package>
|
|
package. This command will report the number of hardware devices
|
|
that is found and give detailed information for each device:
|
|
</para>
|
|
|
|
<screen><prompt>$</prompt> clinfo | head -n3
|
|
Number of platforms 1
|
|
Platform Name AMD Accelerated Parallel Processing
|
|
Platform Vendor Advanced Micro Devices, Inc.</screen>
|
|
|
|
<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
|
|
<package>rocm-opencl-icd</package> package. Adding this package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages"/> enables OpenCL
|
|
support:
|
|
|
|
<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
|
|
rocm-opencl-icd
|
|
];</programlisting>
|
|
</para>
|
|
</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
|
|
<package>intel-compute-runtime</package> package. For Gen7 GPUs,
|
|
the deprecated Beignet runtime can be used, which is provided
|
|
by the <package>beignet</package> package. The proprietary Intel
|
|
OpenCL runtime, in the <package>intel-ocl</package> package, is
|
|
an alternative for Gen7 GPUs.
|
|
</para>
|
|
|
|
<para>
|
|
The <package>intel-compute-runtime</package>, <package>beignet</package>,
|
|
or <package>intel-ocl</package> 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:
|
|
|
|
<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
|
|
intel-compute-runtime
|
|
];</programlisting>
|
|
|
|
</para>
|
|
</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,
|
|
<package>mesa</package> 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 <varname>VK_ICD_FILENAMES</varname>
|
|
environment variable. This variable can contain multiple JSON files, separated by
|
|
<literal>:</literal>. For example:
|
|
|
|
<screen><prompt>$</prompt> export \
|
|
VK_ICD_FILENAMES=`nix-build '<nixpkgs>' --no-out-link -A amdvlk`/share/vulkan/icd.d/amd_icd64.json</screen>
|
|
</para>
|
|
|
|
<para>
|
|
The second mechanism is to add the Vulkan driver package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages"/>. This links the
|
|
ICD file under <filename>/run/opengl-driver</filename>, where it will
|
|
be visible to the ICD loader.
|
|
</para>
|
|
|
|
<para>
|
|
The proper installation of Vulkan drivers can be verified through
|
|
the <command>vulkaninfo</command> command of the <package>vulkan-tools</package>
|
|
package. This command will report the hardware devices and drivers found,
|
|
in this example output amdvlk and radv:
|
|
</para>
|
|
|
|
<screen><prompt>$</prompt> 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</screen>
|
|
|
|
<para>
|
|
A simple graphical application that uses Vulkan is <command>vkcube</command>
|
|
from the <package>vulkan-tools</package> 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 <package>mesa</package>, or the <package>amdvlk</package> package.
|
|
Adding the <package>amdvlk</package> package to
|
|
<xref linkend="opt-hardware.opengl.extraPackages"/> makes both drivers
|
|
available for applications and lets them choose. A specific driver can
|
|
be forced as follows:
|
|
|
|
<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
|
|
pkgs.<package>amdvlk</package>
|
|
];
|
|
|
|
# To enable Vulkan support for 32-bit applications, also add:
|
|
<xref linkend="opt-hardware.opengl.extraPackages32"/> = [
|
|
pkgs.driversi686Linux.<package>amdvlk</package>
|
|
];
|
|
|
|
# For amdvlk
|
|
<xref linkend="opt-environment.variables"/>.VK_ICD_FILENAMES =
|
|
"/run/opengl-driver/share/vulkan/icd.d/amd_icd64.json";
|
|
# For radv
|
|
<xref linkend="opt-environment.variables"/>.VK_ICD_FILENAMES =
|
|
"/run/opengl-driver/share/vulkan/icd.d/radeon_icd.x86_64.json";
|
|
</programlisting>
|
|
</para>
|
|
</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
|
|
(<filename>/dev/dri/renderD*</filename>) or are tagged as
|
|
<code>uaccess</code> (<filename>/dev/dri/card*</filename>). The
|
|
access control lists of devices with the <varname>uaccess</varname>
|
|
tag will be updated automatically when a user logs in through
|
|
<command>systemd-logind</command>. For example, if the user
|
|
<emphasis>jane</emphasis> is logged in, the access control list
|
|
should look as follows:
|
|
|
|
<screen><prompt>$</prompt> getfacl /dev/dri/card0
|
|
# file: dev/dri/card0
|
|
# owner: root
|
|
# group: video
|
|
user::rw-
|
|
user:jane:rw-
|
|
group::rw-
|
|
mask::rw-
|
|
other::---</screen>
|
|
|
|
If you disabled (this functionality of) <command>systemd-logind</command>,
|
|
you may need to add the user to the <code>video</code> 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 <code>dlopen</code>. 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 <package>glibc</package>
|
|
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 <code>LD_DEBUG</code> variable set to get more diagnostic
|
|
information. For example, OpenCL can be tested with
|
|
<code>LD_DEBUG=files clinfo</code>, which should report missing
|
|
symbols.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
</chapter>
|