On Tuesday, 03/16/2010 at 09:36 EDT, Ivan Warren <i...@vmfacility.fr> wrote:
> For all I know, DDR uses 'Read/Write Multiple Count Key and Data' - so > that would mean full track I/O. Ok.. last I looked at it, that was in > VM/SP.. But then again, I think HCPDDR hasn't gone the OCO route yet, so > you could probably look at the source yourself to determine the answer > to your question ! I looked and it wasn't obvious, but, then, I didn't spend too much time looking, either. :-) The definitive answer is to get an I/O trace while you copy a couple of cylinders. DDR makes different choices depending on what it's copying to/from and whether it is running as a guest or standalone. Alan Altmark z/VM Development IBM Endicott
