Hi Tony, 

I've never had occasion to use the "move to primary/secondary or with key" 
instructions either, but one of the programming notes for these instructions in 
the z13 PoOP suggest that performance of these instructions may be 
significantly slower than MOVE (mvc) or MOVE LONG instructions.

There was a discussion on a similar subject a few years back, and I probably 
only remember it because I was asking about boundary alignment and possible use 
of ADM (apparently also known as near-memory copying).  Anyway, I was referred 
to the V2 system optimization primer which contained a page on MVCL* 
instructions on page 31, here... 
https://community.ibm.com/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=d1cdb394-0159-464c-92a3-3f74f8c545c4
   My takeaway was; if you are moving at least 4K and source and target 
locations have at least 4K alignment, then you become eligible for near-memory 
copying, which is quite fast. 

So if you have a need for speed and your copying a lot of data, there may be 
compelling reason not to use those other instructions. 

HTH, 
Mike 

-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On 
Behalf Of Tony Thigpen
Sent: Saturday, April 2, 2022 8:00 PM
To: [email protected]
Subject: Using ARs for MVC vs. using Move to Primary or other instruction?

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All,

I have used ARs to get data from other VSE partitions (address spaces to you 
z/OS guys). I am looking at a program that needs to 'snap shot' a partition by 
copying a lot of data, then printing it.

I have never used "move to primary" or "move with key" type instructions.

Is there any performance, or other reason, I should look at these other 
instructions? Or, should I just continue to use ARs?

Tony Thigpen

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