The developers behind the PlayStation 3 emulator RPCS3 have made a discovery that they say will improve performance in all games across all supported hardware.
According to the developers, team lead Elad discovered new SPU usage patterns that inspired optimized PC code. To showcase the improvements, they posted side-by-side footage of 2012’s Twisted Metal before and after the optimizations along with claims of 5–7% FPS improvements.
The PlayStation 3 is notoriously difficult to emulate, with many in the industry (including a developer on the Twisted Metal team!) long believing that viable emulation was impossible. This is due to the asymmetrical design of the PS3’s Cell processor, which is comprised of a “manager” core and seven SPUs (Synergistic Processing Units), which have no cache and only 256 kilobytes of local storage on each unit. This unconventional architecture requires emulation workarounds that are expensive to perform on traditional CPUs. For example, unlike the general-purpose CPU in your home computer, the PS3’s SPUs couldn’t pull data directly from RAM. Instead, developers had to code direct memory access to pull tiny chunks of data from RAM across seven separate cores. Essentially, a modern CPU emulating the PS3 has to pretend it can’t just grab the data it needs from RAM and, instead, pretend it has seven units pulling seven separate threads of data chunks in parallel.
