Wow, uh no. You&#x27;re 100% wrong, unless I&#x27;m misunderstanding you.  You can absolutely have user code running on N threads simultaneously (where N is the number of cores of your machine).  And you definitely do need mutexes.<p>Your statement holds only if GOMAXPROCS is 1, which granted used to be the default, but was always able to be increased, and the default now is the number of cores on the machine.