I wouldn't be too worried about SMT, my guess is that IBM hasn't done it yet is because it totally trashes the CPU charge-back model.
On second thought, CPU charge back with SMT would seriously penalize code that was not properly optimized for the pipeline, since any stall in a thread would result in the other thread(s) getting a larger share of the execution cycles, hmmm. On Mon, Jun 13, 2011 at 7:11 PM, Farley, Peter x23353 < peter.far...@broadridge.com> wrote: > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On > > Behalf Of Scott Rowe > > Sent: Monday, June 13, 2011 5:07 PM > > To: IBM-MAIN@bama.ua.edu > > Subject: Re: When is performance really an issue? Was: Running an ISPF > > applicction from one pds > > > > If it bothers you that much you are going to have to go back to running > on > > older (slower) hardware. It is just not possible without throwing out > all > > the innovative features that allow current processors to run at the > speeds > > they do. If you think it's bad now, it will get a lot worse if/when IBM > > introduces SMT in mainframe CPUs. > > It's not that I want to go backwards or run on older (slower) hardware. > It's just that in this age of dramatically rising software costs most > managements are asking that existing processes be made as efficient as > possible so that more CPU power does not have to be purchased to do an > increasing volume of work. The only clear measurement of whether you have > improved the efficiency of a program is whether you have reduced the CPU > time it takes to do its job. > > Yesterday that meant run it twice (before and after) and show management > the CPU numbers. Now you must run it 5 or 10 times and show management the > average CPU time of all the runs. > > I know I have to live with that now, but it doesn't mean I have to like it. > In an already-CPU-constrained development environment, running 10 or 20 > tests instead of just 2 takes longer and longer to complete as every other > developer in the same environment is forced to do the same. That frequently > results in weekend work and a lot less "work/family balance". > > Peter > > P.S. -- I googled SMT, and I suspect you're right -- if implemented, SMT > will only make this issue worse. Oh, joy. > > > On Mon, Jun 13, 2011 at 4:20 PM, Farley, Peter x23353 < > > peter.far...@broadridge.com> wrote: > > > > > > -----Original Message----- > > > > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On > > > > Behalf Of Bill Fairchild > > > > Sent: Monday, June 13, 2011 3:50 PM > > > > To: IBM-MAIN@bama.ua.edu > > > > Subject: Re: When is performance really an issue? Was: Running an > ISPF > > > > applicction from one pds > > > > > > > > So what is the "exact" location, velocity, and/or mass of one > > > > particular electron? > > > > > > I didn't mean to ask for "exact", just "nearly the same", not 10% or > > > more different. > > > > > > I know I can't get it, but it's annoying anyway. > -- > > This message and any attachments are intended only for the use of the > addressee and > may contain information that is privileged and confidential. If the reader > of the > message is not the intended recipient or an authorized representative of > the > intended recipient, you are hereby notified that any dissemination of this > communication is strictly prohibited. If you have received this > communication in > error, please notify us immediately by e-mail and delete the message and > any > attachments from your system. > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > CONFIDENTIALITY/EMAIL NOTICE: The material in this transmission contains confidential and privileged information intended only for the addressee. If you are not the intended recipient, please be advised that you have received this material in error and that any forwarding, copying, printing, distribution, use or disclosure of the material is strictly prohibited. If you have received this material in error, please (i) do not read it, (ii) reply to the sender that you received the message in error, and (iii) erase or destroy the material. Emails are not secure and can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by email. Thank you. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
