Were these experiments with MVCOS, MVCL or both? Robert Ngan CSC Financial Services Group
IBM Mainframe Assembler List <[email protected]> wrote on 2015/10/27 17:17:41: > From: "Blaicher, Christopher Y." <[email protected]> > To: [email protected] > Date: 2015/10/27 17:18 > Subject: Re: Moves and others > Sent by: IBM Mainframe Assembler List <[email protected]> > > I did some experiments on a z196 and a z10 to determine that until > you get close to several pages an MVC loop with a final executed MVC > is faster. On those machines the breakeven point was 32K. > The cost is because MVCL and the like are millicode instructions and > there is a fair overhead to starting and ending the millicode > environment. MVCL will kick into a move page shortcut when things > line up on a page boundary, both source and destination, but how > often does that happen? > > Chris Blaicher > Technical Architect > Software Development > Syncsort Incorporated > 50 Tice Boulevard, Woodcliff Lake, NJ 07677 > P: 201-930-8234 | M: 512-627-3803 > E: [email protected] > > -----Original Message----- > From: IBM Mainframe Assembler List [mailto:[email protected] > ] On Behalf Of Robert Ngan > Sent: Tuesday, October 27, 2015 5:27 PM > To: MVS List Server 2 <[email protected]> > Subject: Re: Moves and others > > There's also MVCOS (with zero in R00 for problem state code). It also uses > 2 extra registers (R00, plus a length register). I heard it was > also quite slow compared to MVC, but not sure how it's performance > compares to an executed MVC (or a MVC loop, plus a final executed MVC). > Excluding setup, it's only a single instruction for variable length > moves up to 4K. > > Robert Ngan > CSC Financial Services Group > > IBM Mainframe Assembler List <[email protected]> wrote on > 2015/10/15 18:29:36: > > > From: Robin Vowels <[email protected]> > > To: [email protected] > > Date: 2015/10/15 18:31 > > Subject: Re: Moves and others > > Sent by: IBM Mainframe Assembler List > > <[email protected]> > > > > ----- Original Message ----- > > From: "Paul Gilmartin" > > <[email protected]> > > To: <[email protected]> > > Sent: Friday, October 16, 2015 3:16 AM > > Subject: Re: Moves and others > > > > > > On 2015-10-15, at 08:48, Robin Vowels wrote: > > > > > > IBM should have produced a special EXC instruction for characters, > > > that did what EX does, but accepts k, the number of bytes to move > > (or compare, etc), > > > tests for zero (and performs a no-op if it is), subtracts 1, and > > then executes MVC. > > > > MVCL? > > > > Kind of overkill for small moves. > > 4 registers! > > > > --- > > This email has been checked for viruses by Avast antivirus software. > > http://www.avast.com
