Intel Xeon Phi x200 Series (Knights Landing) and FreeBSD

When we first posted a video with our Intel Xeon Phi x200 developer station booting Windows Server 2012 R2, we immediately got questions regarding FreeBSD. FreeBSD is popular in embedded systems/ computing appliances so several companies working on future FreeBSD products wanted to see if the new Knights Landing chip is compatible. We finally had a few moments to clean up the video around booting FreeBSD with the KNL system from Intel and Supermicro.

Here is the video showing our results testing the Knights Landing system with FreeBSD 11, FreeBSD 10.3 as well as both FreeNAS 9.10-u4 and pfSense 2.3.2:

As you can see, FreeBSD 11 is where you want to start if you are doing Intel Xeon Phi x200 series development on FreeBSD OSes. Those looking for ludicrous ARC cache speeds with ZFS will want to start with FreeBSD 11 (or Ubuntu for that matter.)

Intel Xeon Phi x200 Series Developer Workstation with FreeBSD Results

The final tally of what worked and what did not work:

• FreeBSD 11.0-RELEASE – Works
• FreeBSD 10.3-RELEASE – Does not work
• FreeNAS 9.10-u4 – Does not work
• pfSense 2.3.2 – Does not work

The FreeBSD 10.3 based FreeNAS and pfSense both stopped at “kernel trap 12 with interrupts disabled”. We highly doubt we will see pfSense or FreeNAS systems in production with a KNL chip in the near future but those are very popular FreeBSD distributions so we decided to give them a try.

For those wondering, we have usually seen “kernel trap 12 with interrupts disabled” fixed via BIOS updates. Given the fact that the KNL systems are relatively new, we are going to suggest starting Xeon Phi FreeBSD development with FreeBSD 11 and simply avoiding the 10.x series.  It is likely that the current developer station could get a minor BIOS update and run the older FreeBSD 10.3 distributions. We will submit a request on behalf of the FreeBSD community to see if support can be added in the near future.