Peter, I agree with Edward on this one, ie if you can avoid performing the instruction.
Something you wrote perhaps suggests that it may be a redundant move, <SNIP> I had not thought of the cache-line problem. This particular MOVE is in a subroutine that is invoked multiple times per input record (> 10), which is likely why it is showing up as a spike in Strobe for a file of several million records. </SNIP> If the subroutine is invoked multiple times per input record, can the space move be done just once? Before the subroutine? I recall many years ago in my days at IBM we had a read subroutine. It was the biggest CPU consumer for the least lines of code. This was what it did: (PL/1) INPUT_RECORD = ''; READ FILE(IN) INTO(INPUT_RECORD); RETURN; INPUT_RECORD happened to have about 1200 fields of various types. Since we were reading over that area, the initialise was redundant. We removed the null assign, which PL/I was naturally generating a few thousand instructions for. Problem solved. Regards, On Mon, Aug 10, 2009 at 10:56 PM, Chase, John<[email protected]> wrote: >> -----Original Message----- >> From: IBM Mainframe Discussion List On Behalf Of Robert A. Rosenberg >> >> At 17:31 -0400 on 08/07/2009, Bill Fairchild wrote about Re: z10 and >> overlapping/destructive moves: >> >> >It certainly can't hurt to change the MVI/MVC to a single > instruction: >> > MVC 254(3,120),=120c' ' >> >And, if possible, align the 120c' ' on at least a double word > boundary. >> > >> >Bill Fairchild >> >> I think that should be MVC 254(120,3),=120c' ' >> >> A MVCL might also do the job (if you have the 4 needed registers >> free) and set the from length and location to 0 with x"20" as the >> fill character. > > Probably "better" to use x'40' on an EBCDIC machine.... :-) > > -jc- > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > -- Wayne V. Bickerdike ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
