If you are running DragonFly on a Ryzen CPU, this commit will fix (work around?) a hardware bug. I have not looked at how other operating systems may be addressing it, but it may be interesting to contrast.
A running description of activity related to DragonFly BSD.
Dang, that’s a fun one. Good work on tracking it down and getting AMD to acknowledge it. My experience has been CPU makers don’t want to admit things like this, but wind up releasing firmware updates/microcode patches that make the problem go away (if they can, that is).
Stuff like this is why we need multiple OSes.
This isn’t the first time AMD acknowledged a hardware bug Matt found: http://lists.dragonflybsd.org/pipermail/kernel/2012-March/222494.html