1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

The Virtual GEM Provider Is Still Being Hacked

Linux Kernel

Published on 09 February 2012 11:15 AM EST
Written by Michael Larabel in Linux Kernel
Comment On This Article

VGEM, the Virtual GEM provider for the Linux kernel, is still being developed and a new version has been published.

The Virtual GEM implementation was announced at the beginning of the year by Red Hat's Adam Jackson. Adam began working on this "mock-GEM" implementation so that display drivers without a native DRM driver could use this "fake" kernel driver for memory management. This VGEM driver would then just allocate a shadow frame-buffer while in certain cases like dealing with virtualization the front-buffer could be bound directly to a GEM object, which would eliminate a memory copy and slightly better the performance.

The reasoning for doing this work is to basically improve the CPU-based LLVMpipe driver performance in cases where no GPU driver is available. Running Gallium3D's LLVMpipe software rasterizer is still very slow for OpenGL gaming even with the latest Intel/AMD multi-core CPUs, but it can at least handle desktop compositing. Since late last year the GNOME Shell with Mutter could work with LLVMpipe. Beginning with Fedora 17 and appearing elsewhere is that now when no GPU driver is available rather than falling back to some non-composited desktop mode, LLVMpipe will be called into action with the desktop of choice.

LLVMpipe is alright for this scenario but Adam Jackson has been working on a few performance optimizations, some of which are centered around VGEM for having this fake DRM driver to deal with memory management and to eliminate some memory copy calls.

Since publishing VGEM last month and marking it as being in an alpha state, no new revisions have been published by Adam Jackson. (Among other reasons, he's been working on making the xf86-video-vesa driver work with X.Org Server 1.12.)

This week though Ben Widawsky published a new version of VGEM that builds upon Jackson's work and the comments his first patch revision received. The RFCv2 patch-set can be found on the mailing list.

The reason why Widawsky is playing with VGEM is also interesting. "My intention is to use this to do some dmabuf work/testing with i915 since it seemed too difficult to get some of Dave Airlie's stuff working, and I really don't feel like learning anything about nouveau if I can avoid it. (though I plan to do that later as well)." For those not familiar with DMA-BUF, read this and watch the video.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. AMD R600g/RadeonSI Performance On Linux 3.16 With Mesa 10.3-devel
  2. Intel Pentium G3258 On Linux
  3. SilverStone Precision PS10
  4. ASRock Z97 Extreme6
Latest Linux Articles
  1. Nouveau vs. Radeon vs. Intel Tests On Linux 3.16, Mesa 10.3-devel
  2. KVM Benchmarks On Ubuntu 14.10
  3. X.Org Server 1.16 Officially Released With Terrific Features
  4. Ubuntu With Linux 3.16 Smashes OS X 10.9.4 On The MacBook Air
Latest Linux News
  1. Cauldron 2014: GCC & LLVM Will Look To Collaborate More
  2. GCC Receives ACM Programming Languages Software Award
  3. KDE 4.14 Beta 3 Released
  4. A New Video Has Us Real Excited About The New UT For Linux
  5. CoreOS Experiences Its First Stable Release
  6. GNOME 3.13.4 Continues Working On Wayland & More
  7. Wine 1.7.23 Has Initial Support For 64-bit Android Builds
  8. FreeBSD Developing A New Automounter, Other Features
  9. Guix 0.7 Can Now Install The GNU Operating System
  10. X.Org Foundation Still Works Towards Becoming An SPI Project
Latest Forum Discussions
  1. Debian + radeonsi
  2. Updated and Optimized Ubuntu Free Graphics Drivers
  3. How To Setup Radeon DPM On Ubuntu Linux
  4. Open-source drivers on ATI R7 260X
  5. New build, first Linux PC, what could go wrong? ;)
  6. AMD "Hawaii" Open-Source GPU Acceleration Still Not Working Right
  7. Radeon related kernel bug??
  8. how the US intellegentia operates: