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. Preview: AMD's FX-9590 Eight-Core At Up To 5.0GHz On Linux
  2. Intel Launches The Core i7 5960X, Mighty Powerful Haswell-E CPUs
  3. AMD Radeon R9 290: Gallium3D vs. Catalyst Drivers
  4. AMD Radeon R9 290 Open-Source Driver Works, But Has A Ways To Go
Latest Linux Articles
  1. Ondemand vs. Performance CPU Governing For AMD FX CPUs On Linux 3.17
  2. How Intel Graphics On Linux Compare To Open-Source AMD/NVIDIA Drivers
  3. The Fastest NVIDIA GPUs For Open-Source Nouveau With Steam Linux Gaming
  4. Testing For The Latest Linux Kernel Power Regression
Latest Linux News
  1. Marek Lands Radeon Gallium3D HyperZ Improvements
  2. Mozilla Firefox 32 Surfaces With HTML5, Developer Changes
  3. Nouveau X.Org Driver Released With DRI3+Present, Maxwell, GLAMOR
  4. Microsoft & AMD Release C++ AMP Compiler With Linux Support
  5. AMD, Wine & Valve Dominated August For Linux Users
  6. Linux 3.17-rc3 Kernel Released Back On Schedule
  7. Lennart Poettering Talks Up His New Linux Vision That Involves Btrfs
  8. Mesa 10.3 RC2 Arrives Via Its New Release Manager
  9. Ubuntu 14.10's Lack Of X.Org Server 1.16 Gets Blamed On AMD
  10. MSI Motherboard BIOS Updating Remains A Pain For Linux Users
Latest Forum Discussions
  1. Lennart Poettering Talks Up His New Linux Vision That Involves Btrfs
  2. Best Radeon for a Power Mac G5?
  3. The dangers of Linux kernel development
  4. Updated and Optimized Ubuntu Free Graphics Drivers
  5. AMD Releases UVD Video Decode Support For R600 GPUs
  6. SSD seems slow
  7. Is laptop with Intel CPU and AMD dGPU worth buying considering especially AMD Enduro?
  8. Radeon HD5670 and Ubuntu 14.04