In a new blog post that was published this week, Valve revealed that its Linux port of the popular title Left 4 Dead 2 (L4D2) now outperforms the Windows version of the game on a high-end test rig. The OpenGL-based Linux port of L4D2 runs at 315 FPS, the Direct3D-based Windows version runs at 270.6 FPS, and the OpenGL-based Windows version runs at 303 FPS.

"That the Linux version runs faster than the Windows version seems a little counter-intuitive, given the greater amount of time we have spent on the Windows version. However, it does speak to the underlying efficiency of the kernel and OpenGL," Valve’s Linux team wrote in a blog entry.

Valve announced last month that it was working to bring the Steam game distribution service to Linux, as well as porting its Source game engine and L4D2. The news was welcomed by Linux enthusiasts who recognize it as a major step towards legitimizing the Linux desktop as a consumer platform.

In the original announcement, Valve indicated that it had a working port and said that the next step would be performance optimization. The company has worked to boost the rendering frame rate on Linux so that it could offer a competitive gaming experience to users of the platform. The effort proved more successful than Valve anticipated.

The company says that it is investigating the difference in performance between OpenGL and Direct3D with the aim of getting the Direct3D-based Windows version up to speed with its OpenGL counterpart.

Valve’s software engineers worked several different angles in order to achieve this performance boost. They optimized the game to work better with the Linux kernel, improving the memory allocator and other parts of the stack. They also optimized their OpenGL code to reduce overhead. Finally, they collaborated with hardware vendors to improve graphics drivers.

The latter is especially significant. Hardware vendors have historically not had much of a reason to invest effort into delivering gaming-quality 3D drivers for Linux. The availability of modern gaming titles will raise the bar and motivate the hardware vendors to better support the platform. Such improvements could benefit a large portion of the Linux audience (not just gamers) because modern Linux desktop shells increasingly rely on 3D graphics capabilities and hardware-accelerated rendering.

Intel developer Ian Romanick recently wrote about his experiences working with Valve to improve Intel’s drivers and help the company optimize their game to work better with Intel hardware. In their latest blog post, Valve says that they have also engaged in similar collaborative efforts with NVIDIA and AMD.

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