POWER6/7, compilers and more

By: Anil Maliyekkel (amaliy1.delete@this.nospam.edu), October 3, 2007 8:23 am
Room: Moderated Discussions
Gabriele Svelto (gabriele.svelto@gmail.com) on 10/3/07 wrote:
---------------------------
>David Kanter (dkanter@realworldtech.com) on 10/2/07 wrote:
>---------------------------
>>This one has a roadmap which shows the POWER7 and some vague details, as well as
>>a discussion of the POWER6. At long fucking last, they admitted that the POWER6
>>was an InO core - it only took them about 2 years after they first started talking
>>about it. Hurray for the triumph of technical disclosure over PR and marketing....oh wait.
>
>What's funny about it is that they built an in-order high-clocked core which doesn't
>suck bug time, that's quite an achievement not something that you should be trying to hide.
>
>Gabriele

They have already said that it was in order before. Apparently the only OOO feature is that non-div/sqrt FP instructions can execute in FP unit and finish ahead of an executing div or sqrt.

There was a presentation at the Power Developers Conference last week on the POWER6 core, I managed to get a copy of the PowerPoint file. POWER6 does implement load look ahead, which involves continued dispatch and execution of instructions after a L1-Dcache or D-ERAT miss to initiate prefetches. Despite being in order, POWER6 tracks upto 320 instructions per thread or ten taken branches. It isn't clear to me what number and combination of instructions from two threads can be dispatched. The limit is 7 instructions total and 5 from one thread, but I am still not sure whether only upto 2 from the 2nd thread can be dispatched in the same cycle.
< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
POWER6/7, compilers and moreDavid Kanter2007/10/02 09:36 PM
  POWER6/7, compilers and moreGabriele Svelto2007/10/02 11:32 PM
    POWER6/7, compilers and moreAnil Maliyekkel2007/10/03 08:23 AM
      POWER6/7, compilers and moreanon2007/10/03 08:28 AM
        POWER6/7, compilers and moreAnil Maliyekkel2007/10/03 02:22 PM
      Can you email me the PPT? (NT)David Kanter2007/10/03 08:56 AM
        Me too if you don't mind Anil (NT)Euronymous2007/10/03 12:33 PM
      POWER6/7, compilers and moreLinus Torvalds2007/10/03 09:34 AM
        POWER6/7, compilers and moreAnil Maliyekkel2007/10/03 02:12 PM
          POWER6/7, compilers and moreAnil Maliyekkel2007/10/03 04:06 PM
  POWER6/7, compilers and moreJesper frimann2007/10/03 12:18 AM
  POWER6/7, compilers and moreMr. Camel2007/10/03 02:33 AM
    POWER6/7, compilers and moreasdf2007/10/03 02:08 PM
  POWER6/7, compilers and moreanon2007/10/03 08:09 AM
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