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

Intel's Mesa Driver Gets New Performance Patch

Intel

Published on 19 January 2013 04:34 PM EST
Written by Michael Larabel in Intel
1 Comment

Intel's Mesa DRI driver received a new patch this weekend that's capable of enhancing the open-source graphics driver's performance for some OpenGL games.

The new performance-enhancing Mesa patch is by Kenneth Graunke and entitled i965: Implement CopyTexSubImage2D via BLORP (and use it by default).

CopyTexSubImage2D is now implemented via the BLORP rather than the BLT engine to work around limitations of the latter not being able to blit X-tiled buffers and between buffers of different tiling modes.

In terms of what this patch means for end-users of Intel hardware on Linux, the PlaneShift MMORPG game is much faster. Up to now the game has just run at around one frame per second on Intel hardware while chewing up nearly the entire CPU due to its use of Y-tiled depth buffers with CopyTexSubImage2D. This is a common issue to massively multi-player games.

Additionally, the Xonotic first person shooter with 4x MSAA anti-aliasing is now measured to be about 6.35% faster as a result of this single Mesa patch.

The patch, which adds just over 100 lines of new code to the Mesa i965 DRI driver, can be found currently on the mailing list until it reaches mainline Mesa hopefully in time for next month's Mesa 9.1 release.
The BLT engine has many limitations. Currently, it can only blit X-tiled buffers (since we don't have a kernel API to whack the BLT tiling mode register), which means all depth/stencil operations get punted to meta code, which can be very CPU-intensive.

Even if we used the BLT engine, it can't blit between buffers with different tiling modes, such as an X-tiled non-MSAA ARGB8888 texture and a Y-tiled CMS ARGB8888 renderbuffer. This is a fundamental limitation, and the only way around that is to use BLORP.

Previously, BLORP only handled BlitFramebuffer. This patch adds an additional frontend for doing CopyTexSubImage. It also makes it the default. This is partly to increase testing and avoid hiding bugs, and partly because the BLORP path can already handle more cases. With trivial extensions, it should be able to handle everything the BLT can.

This helps PlaneShift massively, which tries to CopyTexSubImage2D between depth buffers whenever a player casts a spell. Since these are Y-tiled, we hit meta and software ReadPixels paths, eating 99% CPU while delivering ~1 FPS. This is particularly bad in an MMO setting because people cast spells all the time.

It also helps Xonotic in 4X MSAA mode. At default power management settings, I measured a 6.35138% +/- 0.672548% performance boost (n=5).

No Piglit regressions on Ivybridge. I have not tested Sandybridge.

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. Trying The Configurable 45 Watt TDP With AMD's A10-7800 / A6-7400K
  2. Sumo's Omni Gets Reloaded
  3. AMD A10-7800 & A6-7400K APUs Run Great On Linux
  4. Radeon Gallium3D Is Running Increasingly Well Against AMD's Catalyst Driver
Latest Linux Articles
  1. AMD's RadeonSI Driver Sped Up A Lot This Summer
  2. Intel's Latest Linux Graphics Code Competes Against OS X 10.9
  3. Intel Sandy Bridge Gets A Surprise Boost From Linux 3.17
  4. Open-Source Radeon Graphics Have Some Improvements On Linux 3.17
Latest Linux News
  1. The Widely-Criticized New Commercial Linux Distro Is Now On Kickstarter
  2. CUDA 6.5 Is Doing Great For Blender
  3. Wayland & Weston 1.6 Alpha Released
  4. Nouveau Gets Improved Re-Clocking Handling For Select GPUs
  5. A New First-Person Mystery Game Might Be Coming To Linux
  6. Patch By Patch, LLVM Clang Gets Better At Building The Linux Kernel
  7. VC4 Gallium3D Driver Now Handles X With GLAMOR
  8. Opera 25 Development Release For Linux
  9. Steam Now Supports VA-API For In-Home Game Streaming
  10. GNOME 3.14 Beta Released
Latest Forum Discussions
  1. OSS radeon driver for A10-7850K (Kaveri)
  2. Systemd 216 Piles On More Features, Aims For New User-Space VT
  3. Btrfs Gets Talked Up, Googler Encourages You To Try Btrfs
  4. American Citizens running AMOK for food stamps
  5. What Linux Distribution Should Be Benchmarked The Most?
  6. Company I work for is looking to contribute to Open Source projects... but wrongly?
  7. Microsoft vs. Campaign
  8. Updated and Optimized Ubuntu Free Graphics Drivers