AMD Zen likely to get up to 32 cores

Leaked code from a Linux patch suggests that AMD Zen processors may have a maximum of 32 physical cores. The code came to light through Dresdenboy who came across the code on the Linux Kernel Mailing List archive or lkml.org.

According to blogger Dresdenboy, the patch on lkml.org now also shows that the codename Zeppelin is really behind the new Zen processors. Namely, the code states AMD Zeppelin (Family 17h, Model 00h). Earlier patches also referred to a new processor series. That patch only referenced AMD Fam17h.

The most interesting part in the older code from last November is the part that talks about how the last level cache, or llc id, is calculated from the Zen-based MPUs. The code says core complex, but according to Dresdenboy this is comparable to compute unit and has been used in several AMD patents before. There is also a >> 3 in the code, which means that there are eight theoretical cores per compute unit.

Then it says that the socket id is moved to the left by 3, leaving three bits for the core complex id, suggesting a maximum of eight core complexes per socket, or 32 physical cores. Despite the fact that the number should initially be seen as temporary, there are already several rumors that 32 cores could be right.

Code out fix for llc topology for AMD Fam17h systems