The First Experience Of Intel Haswell On Linux

While all of the Linux support is technically there, it's still early support and will continue to be refined. Unfortunately, it seems not everything was completely baked in time.

I've run benchmarks of the Intel Core i7 4770K "Haswell" processor on Linux using the very latest development code for some time. Overall, the experience has been positive, but not everything appears to be in order. As a result, there aren't any Linux benchmarks being shared today.

With the Core i7 4770K with HD 4600 graphics, the Haswell graphics should easily beat out the Ivy Bridge graphics on Linux. However, in the Phoronix testing, this wasn't always the case for a wide array of OpenGL benchmarks. There were also some CPU results that seemed out of order compared to numerous Sandy Bridge and Ivy Bridge processors that were benchmarked on the same software and other hardware components.

In sorting out the issue, I asked one of the Intel Linux graphics driver developers who's been working on the Haswell support (the name's redacted as I deal with the developers directly rather than going through the PR/marketing channels). The developer was a bit surprised by the findings, but said, "I know the performance gap between Linux & Windows is greater on Haswell than it is on Ivybridge - we suspect a kernel issue (power management perhaps?). People are looking into it."

It was also pointed out that even with the Linux 3.10 kernel so far there's an important patch for Haswell that hasn't been merged: drm/i915: Scale ring, rather than ia, frequency on Haswell. This patch may in part be responsible for the performance disparity and further tests are currently being conducted at Phoronix.

In my additional testing in recent days, it appears that indeed there is some possible power management issue occurring for Haswell on Linux leading to less than expected results. The Haswell performance is still great, but just not up to what's expected or found on Windows. With that said, I'm not sharing any Haswell Linux benchmark results in this article but will be saving them for additional articles in the coming days. I remain very confident in Intel's Haswell processors and their success on Linux. The Haswell hardware is very exciting and powerful, so stay tuned for further information.