Is there any reason you aren't using NPTL? Lack of futex-compatible syscall?To be honest, I haven't really investigated if the syscalls used by FreeBSD userland (libkse and libthr) can be used to implement futex funcionality. I believe that porting NPTL to kernel of FreeBSD would require significant effort.
Namely given the usual glibc upstream support for non-linux ports. There is similar syscall in FreeBSD as futex, but it uses long not int. Petr