Actually, no. Irrespective of mkfile being mostly MacOSX specific, most sycalls on MacOSX are just plain slow as compared to Linux (or FreeBSD). I think this is partially an artifact of performance not being a major metric for most system calls on MacOSX. The systems calls where performance is a critical metric (like timekeeping) use a kernel / user shared page interface to avoid the syscall entirely in the vast majority of the cases.
I recall doing benchmarking roughly 10 years ago to find the best interface to communicate with a mostly in an OS-bypass HPC driver. MacOSX ioctls were some multipler more expensive than Linux, but the native IOKit Mach IPC was even more expensive than that. Sigh. There was a similar story for sockets in non-OS bypass mode, where simply writing on a socket was far more expensive than Linux.
Somebody needs to resurrect lmbench & do a comparison of the various x86 kernels available these days. Maybe that would shame Apple into focusing on performance.
Drew