Subj : Re: What is the real costs of LOCK on x86 multiprocesor machine?
To   : comp.programming.threads
From : Sean Kelly
Date : Fri Jul 29 2005 03:50 pm

For what it's worth, the IA-32 Developer's Manual has this to say about
LOCK:

"Beginning with the P6 family processors, when the LOCK prefix is
prefixed to an instruction
and the memory area being accessed is cached internally in the
processor, the LOCK# signal is generally not asserted. Instead, only
the processor's cache is locked. Here, the processor's cache
coherency mechanism insures that the operation is carried out
atomically with regards to memory."

.