AMD Confirms Linux Performance Marginality Problem Affecting Some, Doesn't Affect Epyc / TR
http://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Segv-Response
AMD engineers found the problem to be very complex and characterize it as a performance marginality problem exclusive to certain workloads on Linux. The problem may also affect other Unix-like operating systems such as FreeBSD, but testing is ongoing for this complex problem and is not related to the recently talked about FreeBSD guard page issue attributed to Ryzen. AMD's testing of this issue under Windows hasn't uncovered problematic behavior.
With the Ryzen segmentation faults on Linux they are found to occur with many, parallel compilation workloads in particular -- certainly not the workloads most Linux users will be firing off on a frequent basis unless intentionally running scripts like ryzen-test/kill-ryzen. As I've previously written, my Ryzen Linux boxes have been working out great except in cases of intentional torture testing with these heavy parallel compilation tasks. Even when carrying out other heavy, non-compilation (GCC or Clang) parallel workloads in recent days, from server tasks to scientific processing, my Ryzen test boxes have been stable. I'm still using Ryzen 5 on my main desktop system without any faults in day-to-day use on Fedora 26 Linux.
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