Following yesterday's news that Ubuntu 12.10 will drop the Unity 2D desktop, I carried out some quick tests comparing the latest state of the Unity desktop with Compiz against the lightweight Unity 2D desktop that's now being removed. To not much surprise, the composited Unity desktop still has some performance shortcomings for OpenGL workloads compared to Unity 2D.
The reasoning for dropping Unity 2D is that the Ubuntu developers feel LLVMpipe is now sufficient for handling OpenGL on the CPU for the minority of cases where no supported GPU/driver is available for properly accelerating the Unity desktop. LLVMpipe is capable of doing this efficiently on modern, multi-core hardware with 64-bit support and Fedora has been using LLVMpipe with GNOME Shell for one release already. However, with this dropping of Unity 2D I'm already concerned when it comes to using Unity with LLVMpipe on ARM where the Gallium3D driver is less optimized and I also have concerns about power usage of Unity 2D vs. Unity-over-LLVMpipe. Those concerns will be looked at in future articles, with the focus of today's testing being just to see how the OpenGL gaming performance is comparing between the two desktops.
An Ubuntu 12.10 development snapshot was tested with the latest Unity / Unity 2D desktops of version 6.2.0. The graphics driver stack for the Intel Ivy Bridge hardware was updated to the latest code following the recent Intel Graphics Hit High Point With Linux 3.6 Kernel article from the CompuLab Intense-PC. Intel graphics were used for this quick testing since they're the most common graphics vendor on Linux.
All of the Ubuntu desktop settings remained at their defaults and benchmarking was handled by the Phoronix Test Suite software.