If you are an Intel Haswell ultrabook user and curious whether the Iris Graphics are any faster when switching to one of the newer versions of the Linux kernel, here are some benchmarks.
In not having benchmarked Haswell Iris Graphics on Linux in a few months, using an ASUS Zenbook I ran some fresh kernel comparison tests to see if anything has changed. With Ubuntu 15.10 and its Mesa 11.0.2 user-space driver package, I then benchmarked the Linux 4.1, 4.2 and 4.3 Git kernels from the Ubuntu Mainline Kernel repository.
Note that with Linux 4.3 the default scaling governor for the P-State driver for this Core i7 4558U ultrabook seems to switch from performance to powersave.
In some tests there were slight movements between Linux 4.1 and 4.3, but overall, no big changes. You can see all of my Intel OpenGL Linux results in full via this OpenBenchmarking.org result file
. It's not too surprising the Iris Graphics 5100 performance hasn't changed much on recent kernels given that the open-source Haswell support is already quite mature and the Intel OTC developers have been focusing much of their time lately on Skylake and Broxton graphics work.