On: The Fastest Mutexes

[cesarb]

> But the actual code for YieldProcessor is a NOP on x86:[2]

> __asm__ __volatile__( "rep; nop" : : : "memory" );

It might look like a NOP, but "REP NOP" is not a real NOP, it's the PAUSE instruction (which very old processors from the 1990s treated as a normal NOP).