alt Hacker NewsDoing more system calls isn't really a good idea for performance.
Also if you're doing asynchronous writes you typically can only have one write in-flight at any time, you should aggregate all other buffers while that happens.
Though arguably asynchronous writes are often undesired due to the complexity of doing flow-control with them.
Actually, with newer Linux kernels and io_uring, it appears it is now possible to do multiple writes asynchronously concurrently, by annotating each one with a sequencing constraint.
Whether that's really useful or not depends on whether you do the associated buffer management work.