Pyramid had dual-CPU 90Mx/98x and I think a single lock (memory fades a bit). Later more fine-grained around the time of the 1-CPU 9810 up to 4-CPU 9845. Before eventually going to MIPS CPU SMPs, then adding MPP to the MIPS range.
IIRC, this was on a mostly-BSD 4.2/4.3 base(?) when I worked in the Pyramid team producing their POSIX threads library & parallel debugger (late 80s).
Although Pyramid did have their ATT "unverse" incorporated into the same Unix, hence dualPort. So there was a bunch of SVR3/4 support included: extra set of syscalls; u.u_universe to select which; conditional symbolic links using u.u_universe to resolve to UCB or ATT paths for lib & bin dirs; merged TTY driver with a superset of stty attributes; etc.
Apollo Domain had something similar to conditional symbolic links, but expanding environment variables to determine the target path. Different flexibility/overhead tradeoff.
I wonder if any dualPort or DC/OSx Pyramid source survives...
or the old Australian promo poster from PTC BURP, where I got elected the PHB, standing like a dork at the console of a 9840 cabinet (I think I was the only one in a long sleeve shirt that day, and had an emergency tie at the back of my desk drawer, so...)