Interesting report <https://www.theregister.com/2023/09/27/osseu_steam_os_3/> from the recent European Open Source Summit, about the work being done at Valve and others to improve the ability of the Linux-based Steam Deck handheld console to play games written for Microsoft Windows. And not just to have them playable, but to have them run well, with performance comparable to Microsoft Windows machines. The result, so far, is thousands of games that are usable on the Steam Deck. As a proportion of the total number of games, if I interpret the numbers on the protondb.com home page correctly, that’s 60%—or at least, 60% of games tried by those who submitted reports to the compatibility database. Which is a pretty respectable number. Not enough for world domination yet, but enough to keep the Steam Deck selling, by all accounts. Seems like issues with graphics APIs are not the main problem any more. Now there is a new one: thread/process communication/synchronization primitives. Windows doesn’t use the POSIX/Linux ones, it has a whole set of its own ones, with their own peculiar behaviours. The WINE folks have made a valiant effort to map these onto Linux APIs, but their compatibility layer cannot avoid becoming a performance bottleneck, and it appears this has become a problem for a lot of games. So now there are proposals to add new features to the Linux kernel specifically to make it easier to emulate these idiosyncratic Windows APIs.