[gwmnxnp_516a]

Forking new processes is less efficient than spawning new threads as processes uses more machine resources and more memory. In addition, communication between threads is far more simple than communication between processes. Multicore may not be deal-breaker for server applications, but it matters for applications that require parallel processing.

[gmfawcett]

Forking a process on a modern Linux is relatively cheap these days, and for many jobs you will just prefork all the workers anyway. Passing messages via thread mailboxes or IPC pipes are about equally complex endeavours.

If threads had never been invented, I suspect that 90% of modern multicore programs would have done just fine on a mixture of multi-processing and asynchronous I/O. (The other 10% would have done poorly, though.)

[blacktriangle]

Less efficient for the machine, making the program deal with async is less efficient for the programmer. I'm just confused when I see people working on CRUD apps ruling out tools because they lack first-class async support.