Re: testing HS/SR - 1 vs 2 performance

Simon Riggs <simon@2ndQuadrant.com> writes:
> What I'm not clear on is why you've used a spinlock everywhere when only
> weak-memory thang CPUs are a problem. Why not have a weak-memory-protect
> macro that does does nada when the hardware already protects us? (i.e. a
> spinlock only for the hardware that needs it).

Well, we could certainly consider that, if we had enough places where
there was a demonstrable benefit from it.  I couldn't measure any real
slowdown from adding a spinlock in that sinval code, so I didn't propose
doing so at the time --- and I'm pretty dubious that this code is
sufficiently performance-critical to justify the work, either.
        regards, tom lane