https://bugs.winehq.org/show_bug.cgi?id=43277
--- Comment #37 from Roderick Colenbrander thunderbird2k@gmail.com --- (In reply to Robert Walker from comment #35)
One of the changes AMD with the change to the Ryzen 2000 series was to harmonise the inter-CCX latency with the internal CCX latency.
This change, and general issue, has been covered very well by PC Perspective, e.g.: https://www.pcper.com/reviews/Processors/Ryzen-7-2700X-and-Ryzen-5-2600X- Review-Zen-Matures
As has been stated AMD have implemented an architecture (Zen), which requires NUMA tweaks to obtain optimum performance.
It would be interesting to know if anyone is experiencing this issue with the second generation Ryzen CPUS (2000) and if it is perhaps measureably less severe?
Also the inter-CCX latency is tied to the Infinity fabric speed, which in turn is tied to the system RAM frequency. So again it would be useful to get some performance metrics from Ryzen systems with higher performance system RAM.
Perhaps it would be instructive for AMD Ryzen owners to plot their own system inter-CCX times?
At this stage it is best to find more games which are truly affected by this issue and on which performance can be fixed using CPU pinning tricks.
My feeling the issue if you can call it one, is a Linux kernel problem though we need more evidence. I suspect the Windows kernel may have received more consumer application tweaking. AMD worked with Microsoft extensively (in the beginning it didn't report SMT correctly, cache sizes, but they also did many tweaks). Depending on how implemented some of these tunings may even be considered 'hacks'. Again first we need to gain more evidence on which applications are affected and find some patterns.