Wine developer Zebediah Figura has sent in a proposal to work on a new Linux Kernel interface for Wine synchronization primitives, one that gets closer to performance and behaviour of Windows NT.
The basic idea is that the Wine team are "looking to introduce a kernel API that will allow us to implement Windows NT synchronization object API with at most one syscall per operation, and without managing object state in user managed shared memory, for the sake of performance". This might sound familiar if you follow Wine and Steam Play Proton closely, as it's part of what both esync and fsync were supposed to help with.
What's the deal? As Figura explained, modern games that need high performance make heavy use of multiple threads and synchronization primitives which Wine needs to work with in a way that's accurate and performs well. Both esync and fsync can give big boosts to performance of Windows games on Linux through Wine but it's mentioned that each also has big problems of their own.
Figura goes on to give a proposal of what the interface could look like, to gather feedback. Since this is in the very early stages, we're likely some time away from seeing it come to fruition.
The full post on the mailing list which goes into the deep details can be read here.