Batching syscalls is on my mind. The architecture of Fusion will revolve around channel-based ipc (both sync and async), including between user mode and kernel mode. The end state I'm aiming for is an async channel for syscalls, where the user task issues syscalls, which get buffered in a queue, where the kernel processes the queue asynchronously.

For this to work properly, user tasks need to be able to respond to completed syscalls async as well. That's why my idea of user tasks is that they should be modeled as state machines, with channel-based events as the core mechanism by which code gets executed in a deterministic manner. The equivalent of signals in Unix (which many find one of the bad aspects of Unix design) would be receiving events on one or more channels for various purposes (e.g. IO completion, timers, abort, interrupt, GUI events, etc.).