On Friday 19 November 2010 17:25:57 Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > Locked statments like 'lock xaddl;' guarantee that the specific operands
> > (or their cachelines) are visible on all processors and are done
> > atomically - but its not influencing the whole cache like mfence would.
> Where is this "locking the whole cache" meme coming from? What we're
> looking for has nothing to do with locking anything. It's primarily
> a directive to the processor to flush any dirty cache lines out to
> main memory. It's not going to block any other processors.
I was never talking about 'locking the whole cache' - I was talking about
flushing/fencing it like a "global" read/write barrier would. And "lock
xchgb/xaddl" does not imply anything for other cachelines but its own.
I only used 'locked' in the context of 'lock xaddl'.
Am I misunderstanding you?
Andres