Intel Skylake HD Graphics 530 Performance On Linux
Intel's Core i5 6600K and i7 6700K processors released earlier this month feature HD Graphics 530 as the first Skylake graphics processor. Given that Intel's Open-Source Technology Center has been working on open-source Linux graphics driver support for over a year for Skylake, I've been quite excited to see how the Linux performance compares for Haswell and Broadwell as well as AMD's APUs on Linux. In this article is the first of these OpenGL benchmarks comparing the Core i5 6600K to other offerings from Intel and AMD.
The Intel HD Graphics 530 on the Core i5 6600K have a base frequency of 350MHz and a maximum frequency of 1.15GHz. The HD Graphics 530 supports addressing up to 1.7GB of system memory, boasts 24 execution units, supports 4K @ 60Hz, three displays can be driven at once, and is capable of OpenGL 4.3 / DirectX 11.2 / DirectX 12_1. The HD Graphics 530 should end up being a nice upgrade over Haswell's HD Graphics 4600 found on the Core i7 4770K and 4790K. However, the HD Graphics 530 aren't meant to compete with Broadwell's Iris Pro 6200 Graphics as found on the Core i7 5775C socketed Broadwell processor. We'll need to wait a while before seeing Skylake Iris Graphics with an eDRAM cache in socketed, desktop form.
The Core i5 6600K and Core i7 6600K launched two weeks ago but availability on these processors remain quite limited. Due to the limited availability, I didn't have a review sample for launch-day testing from Intel PR, but am still waiting. Last week I ended up buying a i5-6600K after getting lucky in finding one in stock at a popular retailer and thus that's the sole Skylake processor being tested for today's article. Hopefully Intel will be able to send over an i7-6700K soon for complementary Linux testing.
Using the HD Graphics 530 on Linux on Ubuntu 15.04 and Fedora 22 has been going well over the past week, with one annoyingly silly exception: needing to pass a kernel argument to actually get graphics support. Even with the Linux 4.2 kernel users still need to set i915.preliminary_hw_support=1 in order to actually enable the i915 DRM driver to provide kernel mode-setting and hardware acceleration. See the aforelinked article for more details.
Aside from needing to set this kernel option seemingly until at least Linux 4.3, things on my end have been going well. However, other early Skylake Linux users have reported some problems... Namely, this bug and it seems to primarily hurt KDE users. Under GNOME and Ubuntu Unity, I haven't run into such problem. The support overall seems pretty much on par with Haswell and Broadwell graphics under Linux.
Within the latest Mesa Git code at the moment, the Intel Mesa driver is exposing OpenGL 3.3 support while OpenGL 4.3 is what's supported by the hardware. Intel is close with Linux OpenGL 4 support but it doesn't look like they'll achieve that milestone for Mesa 11.0 due next month. That will mean there won't be OpenGL 4.0~4.2 for the Intel Linux graphics stack in released form until three months later with the next Mesa update, there's just a few GL 4.0/4.1 extensions left blocking them from compliance in their driver.
Beyond OpenGL there is OpenCL for Skylake with Beignet 1.1 that is currently OpenCL 1.2 conformant. Sadly there hasn't been much work lately on Beignet's OpenCL 2.0 Git branch. The video acceleration support continues to be provided by the VA-API implementation and since earlier this year has HEVC/H.265 encode/decode support as handled by Skylake's hardware.