100 nanoseconds out of 1 millisecond is 1/10000 or ~0.01% which is really not very significant. As I said, if you have hot loops with a 1 microsecond budget the

100 nanoseconds out of 1 millisecond is 1/10000 or ~0.01% which is really not very significant. As I said, if you have hot loops with a 1 microsecond budget then you might see material benefits with a kernel architecture that requires fewer privilege crossings. However, in most such cases there are fairly easy ways of reorganizing the code to use the system architecture more efficiently, such as by batching multiple writes in userspace, that will also result in fewer syscalls in your critical path (and thus fewer privilege crossings) without changing the kernel architecture. It is actually a fairly rare problem where the only solution is to issue a vast numbers of syscalls quickly and in those cases that is usually a limitation of the kernel data structures and syscall implementation. Just to clarify the distinction, in the former you issue the same number of "syscalls", but the new kernel architecture results in fewer privilege crossing events where as my statement here is to rearchitect so you need to issue fewer syscalls.