While the Intel Direct Rendering Manager driver is only part of the the Intel Linux graphics stack -- with Mesa being important as well as xf86-video-intel, libdrm, VA-API, etc -- being tested today was the OpenGL performance from the Core i5 4670 system when testing all the recent major kernel releases during Haswell's tenure.
Testing happened from Ubuntu 14.04 with Mesa 10.1-devel and other xorg-edgers packages. The only change between kernel tests was installing the mainline kernel release and rebooting, followed by firing up the Phoronix Test Suite for automated testing.
All of the results and system information in full is hosted on OpenBenchmarking.org.
Overall, these Core i5 Haswell results aren't too exciting besides seeing a modest bump with the Linux 3.10 kernel. However, when factoring in the Mesa changes and such, Intel Haswell's performance improved a lot in 2013 after the hardware's debut.
In regards to the recently reported possible Intel Haswell Linux regression, the latest look after further testing and using additional hardware is it appears to not be related to the graphics driver but possibly some weird hardware interaction issue between the particular motherboard's UEFI and the latest Linux kernel.
See the rest of today's data on OpenBenchmarking.org.