Navi Linux driver code confirms GCN design, but does that matter?

Navi Linux driver code confirms GCN design, but does that matter?

Navi Linux driver code confirms GCN design, but does that matter?

AMD has started to push out the first few hints of Navi into their Open-Source Radeon drivers, paving the way towards next-gen Navi graphics support. In AMD’s latest driver commits, references to “gfx1010” have been uncovered, hinting at a 10th generation graphics architecture that will succeed AMD’s 9th Generation Vega microarchitecture. 

One specific reference has been sparking some controversy amongst hardware circles, with references to “EF_AMDGPU_MACH_AMDGCN_GFX1010″ suggesting that Navi will be another iteration of AMD’s GCN architecture, leading to comments on Twitter and Reddit which claimed that Navi was “Dead on arrival”, or will otherwise be underwhelming. 

This leads to an obvious question. Does it matter if Navi is another iteration of AMD’s GCN architecture? The answer is more complicated than a simple yes or no. 

AMD’s Graphics Core Next (GCN) is both a graphics architecture and the name of its underlying instruction set, having replaced Radeon’s older TeraScale microarchitecture/instruction set in 2012 with the release of their HD 7000 family of graphics cards. When AMD references Navi as a GCN graphics card, what they mean is that Navi will continue to use the same instruction set architectures as Vega, Polaris and older GCN-based graphics cards, with Navi being the latest and most refined graphics architecture to be based on that instruction set. 

So does it matter that Navi is still a GCN part? Not really, remember that both AMD and Intel still build processors that are based on the x86 instruction set. A lot of hardware/architectural changes can take place while retaining the same instruction set. The same thing also applies to Nvidia, whose architectures have seen significant changes over the years, but at their core remain very similar to what came before. Nobody complains when they hear that Nvidia’s next-generation offerings will continue to use CUDA cores… 

Does AMD need to create a new graphics ISA (instruction set architecture) to make Navi a big improvement over Vega? No, there are many ways to skin a cat and AMD likewise has many avenues that can be explored to improve the performance of their graphics cards. 

 Navi Linux driver code confirms GCN design, but does that matter? 

If you want to complain about Navi being another GCN-based architecture, you must remember that AMD can make some sweeping changes with Navi and still call itself a GCN graphics card. At this time relatively little is known about AMD’s Radeon Navi architecture, but we do know that it will power the next generation of high-performance consoles. As such, Navi will likely include major improvements that will come thanks to what Radeon has learned through working with both Sony and Microsoft on today’s PlayStation and Xbox consoles, as well as their enhanced Pro/X variants. 

We should expect to learn more about AMD’s Radeon Navi architecture later this year, likely at Computex and E3 2019, with a release that will likely occur in Summer 2019. Navi may be a GCN-based graphics card, but that doesn’t mean that their new architecture can’t be a major improvement over Vega. 

You can join the discussion on AMD’s Navi architecture continuing to be GCN-based on the OC3D Forums.