IIRC, the S/370s were somewhat affected by non-aligned doublewords, and the impact has decreased with newer hardware, possibly to zero or nearly so. If I had to guess, micro code advances, faster multi-level cache, and/or out of order execution, have made any impact negligible.
On Oct 7, 2017 3:10 PM, "scott Ford" <idfli...@gmail.com> wrote: > Peter, > > Loved the answer.. Would you agree how the macros is used and purpose being > factors in performance, speaking very > Generically.. > > > Scott > > On Sat, Oct 7, 2017 at 9:01 AM Peter Relson <rel...@us.ibm.com> wrote: > > > It signifies what you expect it to signify, but not down to the level of > > micro-managing. I would view the difference between doubleword alignment > > and not-so-aligned to be micro-managing, > > > > > I don't recall ever seeing a value other than "None," > > There are some (maybe even many). GQSCAN, for example. > > > > Primarily I would think it might apply to operational differences between > > choices when it seems important to let the user know. > > > > Peter Relson > > z/OS Core Technology Design > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > -- > Scott Ford > IDMWORKS > z/OS Development > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
