Re: Let's drop support for named POSIX semaphores

Peter Eisentraut <peter(at)eisentraut(dot)org> writes:
> There were some recent discussions about removing the requirement of
> SysV IPC to allow macOS sandboxing mechanisms to be used. These
> discussions mainly focus on SysV shared memory, which is currently a
> hard requirement, but I would expect that switching to non-SysV
> semaphores would be part of such an undertaking. So I think adding
> another hard requirement on SysV IPC would not be preferable.

Named POSIX semaphores are not a credible replacement for SysV
semaphores, because of their performance issues (which are just
as real on macOS as anywhere else). So I think the direction we'd
have to go in to make that happen is to replace all the semaphore
stuff with futexes or some other low-level primitive, as Munro
speculated about in one of the threads I cited.

regards, tom lane