On 9 January 2012 04:40, Hobart Spitz <[email protected]> wrote:
> Suppose you wanted to move a large amount of data, and there are many page
> faults involved.  If you divide the moves into logical sections, and do
> each of the section moves in turn with MVCLE, you could go on to the next
> when one is interrupted.  Doing this in a round-robin fashion, you could
> have your page faults being serviced in parallel.  This could cut your move
> time by roughly the reciprocal of the number of sections.  It's a bit out
> there for applications, but program products (like DB2, sort, etc.) might
> benefit from such a technique.
>
> This is just speculation, but given the orders of magnitude difference
> between CPU speed and I/O speed could this explain be the reason for the
> CC=3 condition?

I don't think it works. You can't both have a CC=3 from the
instruction, *and* have it cause a page fault. Even if the
hardware/millicode chooses to give you a CC=3 when it can't resolve an
address, there is no way for you to know that that's the problem. You
could, I suppose, assume that that's what went wrong, and issue your
own (async) pagein, but it doesn't sound like a very predictable
business.

Tony H.

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