On a 600 MIPS single engine (z/990 class) 1,000,000 instructions is 0.17% of a CP. These days?
- -teD - Original Message From: John McKown Sent: Monday, February 17, 2014 13:15 To: [email protected] Reply To: IBM Mainframe Discussion List Subject: Re: Branch (was: Performance question - adding) On Mon, Feb 17, 2014 at 12:03 PM, Paul Gilmartin <[email protected]>wrote: > On 2014-02-17, at 10:36, Ted MacNEIL wrote: > > > I have to ask: Why they big concern over a few instructions? > > Optimisation of a few is not worth the > effort these days. > > > Hmmm... No single instruction is worth optimizing. > > No single instruction among a million is worth optimizing. > > It's not worth optimising a million instructions because > that would imply optimizing each, which is not worth it. > > E.E. asked whether the code is in a loop. > > -- gil > > I guess that I ASSuMEd that the code was in a heavily used loop. If you remove 1 instruction from a loop which is executed a million times, assuming the instruction is "expensive", then it may well be worth the effort. Or maybe even replacing it with two "simpler" instructions (such as my thought on using IPM and SPM with an STOC instead of a JZ and ST). -- Wasn't there something about a PASCAL programmer knowing the value of everything and the Wirth of nothing? Maranatha! <>< John McKown ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
