I doubt that they care. In the period where I worked on Mac drivers and kept close track of the Darwin sources (roughly 2003->2013) I saw very little in the way of performance improvements.
AFAIK, they still don't support 15 year old technologies like MSI-X that permit efficient multi-queue network drivers.
Have you ever built a project by hand on MacOS and then on Linux (or FreeBSD)? Have you noticed how absurdly, painfully slow it is running autoconf on MacOSX? That's because MacOS system calls are horrifically slow compared to Linux / BSD.
It's `fork` in particular which is much slower. It has to fiddle with Mach port rights, doesn't do overcommit, etc. And autotools is very fork heavy.
Apple provides posix_spawn which is much much faster. Running /usr/bin/false 1000 times in the fish shell is nearly twice as fast (2.25s to 1.25s) when using posix_spawn instead of fork, on the Mac.
Autotools doesn't use posix_spawn because there's no benefit on Linux, but it is what Apple's frameworks use internally for process launching.
Small number of minutes vs less than a minute. The last time I built something by hand in both places, it seemed to take 2x to 3x as long to run all the autoconf checks on MacOS. That's basically a fork / exec / open /close sort of benchmark.
Spent a while thinking why I don’t see this much. I work mostly with higher level languages, so the beefiest things I run are probably webpack and the typescript language server. I wonder if maybe the problem is fork or some derivative effect. That, or I just don’t have any syscall heavy loads in my life, full stop.
It doesn't need autoconf to see this. I have seen it in a project with a simple make -j, compiling with clang in both places. Builds finish much faster on Linux.
To be fair this may be many things and not just mach syscalls.
