Using OpenCL with Intel GPU on Linux

[kohrt]

Thanks to the work of @masterhui, we have instructions to get OpenCL running on Intel GPUs using Beignet. I think this is useful for many people here too. The original thread is code-iai/iai_kinect2#11.

Known configuration

• Ubuntu 14.04
• Kernel 3.13 (>= 3.13.0-35-generic) or Kernel 3.16 (needed for the Intel USB 3.0 Controller)
• Beignet v1.0 (http://www.freedesktop.org/wiki/Software/Beignet/)

Dependencies for Beignet

For Beignet the following depencies have to be installed manually:

• ocl-icd-dev
• ocl-icd-libopencl1
• libdrm / libdrm-dev
• llvm-3.5 / llvm-3.5-dev
• clang-3.5 / clang-3.5-dev
• libegl1-mesa-dev
• libedit-dev

Building Beignet

Download and compile the Beignet v1.0 release from source (there is a Beignet_v0.3 binary for Trusty, but it is very old, buggy and slow)

Additional steps (if needed):

• Error "clang: not found":

  sudo ln -s /usr/lib/llvm-3.5/bin/clang /usr/bin/clang
  

• Known Beignet issue with Kernel 3.15/3.16 (see Beignet readme); fix is to disable cmd_parser:

  sudo su
  echo 0 > /sys/module/i915/parameters/enable_cmd_parser
  

• To get 100% pass rate on the Beignet unit tests you may have to:

  • Execute directly on hw: ssh-session might not work
  • Execute as root

Note: Both previous points have to to with the fact that no x-server was installed. Apparently this will be fixed in a future release of Beignet.

Results on Intel i7-3840QM (mobile hardware)

• ~100 fps on the OpenCLDepthPacketProcessor (compared to < 5 fps on same hardware using CPU-based depth registration!)

  ...
  [OpenCLDepthPacketProcessor] avg. time: 10.1716ms -> ~98.3129Hz
  [TurboJpegRgbPacketProcessor] avg. time: 16.0787ms -> ~62.194Hz
  ...
  

[floe]

+1 Great to hear, thanks for the heads-up! Does it also work with beignet-0.3 from Trusty, just slower, or not at all?

[masterhui]

I didn`t get it to work, not sure any more which specific errors I was
seing at the time, sorry. But now that I know it does work at all, I could
revert back to the 0.3 binary release of Beignet and do some testing. I'll
let you know what I find once I get back to it.

On Tue, Dec 2, 2014 at 2:37 PM, Florian Echtler notifications@github.com
wrote:

+1 Great to hear, thanks for the heads-up! Does it also work with
beignet-0.3 from Trusty, just slower, or not at all?

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#109 (comment)
.

[spiralray]

Hey, I made scripts for installing Beignet 1.0.0 on Ubuntu 14.04
https://gist.github.com/spiralray/cae0bc235509e495fec1

If your CPU is haswell series, you have to build patched linux kernel manually.
So do "sh build_kernel.sh" and "dpkg -i /usr/src/linux-*.deb".

After installing kernel, reboot and launch disable_cmd_parser.sh

[masterhui]

Hi spiralray,
Great work, this makes things so much easier! I will try it out when I do
my next machine install/upgrade and report back. Cheers!

On Mon, Dec 15, 2014 at 6:07 PM, spiralray notifications@github.com wrote:

Hey, I made scripts for installing Beignet 1.0.0 on Ubuntu 14.04
https://gist.github.com/spiralray/cae0bc235509e495fec1

If your CPU is haswell series, you have to build patched linux kernel
manually.
So do "sh build_kernel.sh" and "dpkg -i /usr/src/linux-*.deb".

After installing kernel, reboot and launch disable_cmd_parser.sh

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#109 (comment)
.

[ricardborras]

Hi spiralray,

I have tried your script and it is not able to build Beignet. It complains about
/home/rborras/beignet/Beignet-1.0.0-Source/backend/src/llvm/llvm_bitcode_link.cpp:42:32: fatal error: llvm/Linker/Linker.h: File does not exists
#include "llvm/Linker/Linker.h"

Looking at beignet code, it seems that it has issues with LLVM_VERSION_MINOR which is equal to five in my case, and should be 4 (and include properly Linker.h). Has anyone experienced this?

Thanks,

Ricard

[BennyRe]

I had the same issue with the headers being somewhere else, when I tried to install Beignet by hand.
I didn't search for an answer.

[kohrt]

It's a problem of the Ubuntu llvm package. https://bugs.launchpad.net/ubuntu/+source/llvm-toolchain-3.5/+bug/1372062
If you download llvm and clang from their website pre-build for Ubuntu it should work fine.

[spiralray]

Beignet supports LLVM 3.4 and 3.5, so I avoided this issue uninstalling LLVM-3.5.

sudo apt-get remove llvm-3.5* clang-3.5*

[spiralray]

Hey, I modified my scripts for using LLVM-3.5.
This script, install_beignet.sh, installs llvm package from official website
http://llvm.org/releases/download.html

So, Uninstall LLVM package released from Ubuntu repository first.

sudo apt-get remove llvm-3.5* clang-3.5* llvm-3.4* clang-3.4*

Then, run

sh install_beignet.sh

[ricardborras]

Hi,

after using your modified script, I get an error on llvm-config when beignet is built:
cmake ../
-- The C compiler identification is GNU 4.8.2
-- The CXX compiler identification is GNU 4.8.2
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Found PkgConfig: /usr/bin/pkg-config (found version "0.26")
-- Building mode: RelWithDebInfo
-- LLVM llvm-config found at: /usr/local/bin/llvm-config
/usr/local/bin/llvm-config: 1: /usr/local/bin/llvm-config: Syntax error: ")" unexpected
CMake Error at CMake/FindLLVM.cmake:32 (string):
string sub-command REGEX, mode REPLACE needs at least 6 arguments total to
command.
Call Stack (most recent call first):
CMakeLists.txt:97 (Find_Package)

CMake Error at CMake/FindLLVM.cmake:34 (message):
imcompatible LLVM version required 3.3
Call Stack (most recent call first):
CMakeLists.txt:97 (Find_Package)

If I run llvconfig from console, I get:
sudo llvm-config
/usr/local/bin/llvm-config: 1: /usr/local/bin/llvm-config: Syntax error: ")" unexpected

Clearly is a llvm error, anyone has a solution?

Thanks,

Ricard

[BennyRe]

The script works for me but now the Protonect example just segfaults. The last commit that doesn't segfault is e6f6a43

gdb outputs this:

(gdb) r
Starting program: /home/iki/libfreenect2/examples/protonect/bin/Protonect 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x0000000000604291 in shutdown ()

Anyone else having this problem?

[spiralray]

Sorry, everyone.
I only checked beignet was installed, and I didn't check whether libfreenect2 worked.
I tested, and I met the same issue.
I tried with i7-4600U and i7-4770R using kernel 3.16.7-ckt1( which is built by "build_kernel.sh"), but both of them did't work.
Here is my log files.
https://gist.github.com/spiralray/a1cfd101b75705afbbbf

BennyRe, What CPU you use?
Is it a problem with Haswell model?

is This problem related to the OpenCL extension "cl_khr_gl_sharing"?
In my environment, "cl_khr_gl_sharing" is not enabled.
So, if it is needed, we have to compile Mesa.

[BennyRe]

I'm on a i5-4690 so yes it is Haswell.