[Beowulf] Intro question

[Greg Lindahl]

On Mon, Dec 08, 2008 at 10:19:17AM -0500, Lawrence Stewart wrote:

> Well <of course> the NIC should read from cache or update the cache if the
> data happens to be there. Don't all well designed I/O systems do that?

There are a small number of systems that don't. Needless to say, it's
a bit confusing for library writers to get I/O right in that
circumstances.

BTW, any interconnect that sends messages using PIO sends from
cache. I wish people would invent a real receive-to-cache, since it
would be nice overhead reducer for small messages on InfiniPath -- a
small latency benefit (~ 7%), a bigger overhead benefit (~ 15%).

-- greg