ISSCC Poulson Preview Online - OoO not unlikely?

Article: New Itanium Microarchitecture at ISSCC 2011
By: anon (anon.delete@this.anon.com), November 17, 2010 5:38 pm
Room: Moderated Discussions
Linus Torvalds (torvalds@linux-foundation.org) on 11/17/10 wrote:
---------------------------
>anon (anon@anon.com) on 11/17/10 wrote:
>>
>>Avoiding OoO probably made a lot more sense 10 years ago than it does now.
>
>So I'm on record for (many times) saying that I'd love to
>see an OoO Itanium.
>
>But one reason I'd love to see it is because I think it
>would be very interesting and challenging to do. Some of
>the features of the Itanium architecture are nasty from
>an OoO standpoint.
>
>Predication is nice and simple for in-order cores. But it's
>generally really nasty for OoO because it makes for big
>uglyy data dependencies. Sure, you can fix that - using
>prediction for predication is as valid as it is for any
>normal conditional branch - but code that is compiled with
>predication in mind tends to use it heavily for both the
>nicely predictable cases and for unpredictable ones.

Well control dependencies obviously depend on the correct execution of the branch (which ends up having exactly the same data dependency to resolve the branch). So for nasty unpredictable conditionals, you want to use prediction and no speculation.

Couldn't they just tweak compilers to be more like x86 one in terms of when a predicated sequence is considered a win?
< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
ISSCC Poulson Preview OnlineDavid Kanter2010/11/17 03:40 AM
  ISSCC Poulson Preview Onlinesavantu2010/11/17 05:25 AM
  ISSCC Poulson Preview Onlinesomeone2010/11/17 08:51 AM
    ISSCC Poulson Preview OnlineLinus Torvalds2010/11/17 09:27 AM
      ISSCC Poulson Preview Onlinesomeone2010/11/17 10:31 AM
        ISSCC Poulson Preview OnlineRichard Cownie2010/11/17 10:55 AM
          ISSCC Poulson Preview OnlineLinus Torvalds2010/11/17 11:30 AM
          ISSCC Poulson Preview Onlinesomeone2010/11/17 11:42 AM
            ISSCC Poulson Preview Onlinea reader2010/11/17 02:07 PM
        ISSCC Poulson Preview OnlineGabriele Svelto2010/11/19 02:52 AM
          ISSCC Poulson Preview Onlinesavantu2010/11/19 05:37 AM
    ISSCC Poulson Preview OnlineDavid Kanter2010/11/17 12:12 PM
      ISSCC Poulson Preview Onlinesomeone2010/11/17 12:40 PM
        ISSCC Poulson Preview OnlineDavid Kanter2010/11/17 02:08 PM
          ISSCC Poulson Preview Onlineajensen2010/11/18 01:24 AM
  ISSCC Poulson Preview Onlinelubemark2010/11/17 09:52 AM
  ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/17 11:41 AM
    ISSCC Poulson Preview Online - OoO not unlikely?Linus Torvalds2010/11/17 12:12 PM
      ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/17 05:38 PM
        ISSCC Poulson Preview Online - OoO not unlikely?Linus Torvalds2010/11/17 08:03 PM
    ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/17 12:14 PM
      ISSCC Poulson Preview Online - OoO not unlikely?Richard Cownie2010/11/17 02:07 PM
        ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/17 02:59 PM
          ISSCC Poulson Preview Online - OoO not unlikely?sylt2010/11/17 03:26 PM
          ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/17 05:53 PM
            ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/17 08:34 PM
              ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/17 09:22 PM
              ISSCC Poulson Preview Online - OoO not unlikely?Martin Høyer Kristiansen2010/11/18 12:35 AM
                ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/18 01:14 AM
                  ISSCC Poulson Preview Online - OoO not unlikely?Martin Høyer Kristiansen2010/11/18 02:00 AM
          ISSCC Poulson Preview Online - OoO not unlikely?Groo2010/11/18 03:28 PM
            ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/18 09:30 PM
              ISSCC Poulson Preview Online - OoO not unlikely?Doug Siebert2010/11/19 12:06 AM
                ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/19 07:52 AM
                  Negativity and ignorancePaul A. Clayton2010/11/19 06:11 PM
                  rhetoricshobold2010/11/20 05:01 AM
              ISSCC Poulson Preview Online - OoO not unlikely?anonymous2010/11/19 02:17 AM
                ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/19 08:22 AM
                  ISSCC Poulson Preview Online - OoO not unlikely?Linus Torvalds2010/11/19 09:26 AM
                    ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/19 11:04 AM
                      ISSCC Poulson Preview Online - OoO not unlikely?Linus Torvalds2010/11/19 11:24 AM
                        ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/19 12:05 PM
                          ISSCC Poulson Preview Online - OoO not unlikely?Linus Torvalds2010/11/19 01:08 PM
                            ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/20 11:02 AM
                              ISSCC Poulson Preview Online - OoO not unlikely?dc2010/11/20 12:59 PM
                              ISSCC Poulson Preview Online - OoO not unlikely?dc2010/11/20 01:01 PM
                                ISSCC Poulson Preview Online - OoO not unlikely?rwessel2010/11/20 01:27 PM
                                  ISSCC Poulson Preview Online - OoO not unlikely?dc2010/11/21 05:00 PM
                                    single-system single-location != RASanonymous2010/11/21 09:33 PM
                                      single-system single-location != RASdc2010/11/25 12:06 PM
                                        single-system single-location != RASDavid Kanter2010/11/25 01:58 PM
                    CS:SNAREPslacker2010/11/20 04:07 AM
                      CS:SNAREPnone2010/11/20 04:53 AM
                        CS:SNAREPS. Rao2010/11/20 11:20 AM
                      CS:SNAREPGabriele Svelto2010/11/22 07:11 AM
                  ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/19 11:08 AM
                    ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/19 06:51 PM
                      ISSCC Poulson Preview Online - OoO not unlikely?rwessel2010/11/20 01:53 AM
                        ISSCC Poulson Preview Online - OoO not unlikely?dc2010/11/20 12:43 PM
                          ISSCC Poulson Preview Online - OoO not unlikely?anon2010/11/20 05:43 PM
                            ISSCC Poulson Preview Online - OoO not unlikely?Foo_2010/11/20 05:56 PM
              ISSCC Poulson Preview Online - OoO not unlikely?Groo2010/11/20 12:59 PM
                P = E/tslacker2010/11/20 11:31 PM
                  P = E/tAndi Kleen2010/11/21 03:02 AM
                ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/21 10:24 AM
                  ISSCC Poulson Preview Online - OoO not unlikely?Richard Cownie2010/11/21 01:07 PM
                    ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/21 04:50 PM
                      ISSCC Poulson Preview Online - OoO not unlikely?Richard Cownie2010/11/21 05:38 PM
                        ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/21 06:27 PM
                          ISSCC Poulson Preview Online - OoO not unlikely?Richard Cownie2010/11/22 08:37 AM
                            ISSCC Poulson Preview Online - OoO not unlikely?someone2010/11/22 09:07 AM
                              ISSCC Poulson Preview Online - OoO not unlikely?Richard Cownie2010/11/22 09:25 AM
                                ISSCC Poulson Preview Online - OoO not unlikely?dc2010/11/25 12:22 PM
                                  ISSCC Poulson Preview Online - OoO not unlikely?Richard Cownie2010/11/26 10:44 AM
                              perfAM2010/11/24 03:28 AM
                                perfajensen2010/11/24 03:46 AM
                                perfsomeone2010/11/24 09:59 AM
                          OOOE and energy efficiencyDavid Kanter2010/11/23 11:28 AM
                            OOOE and energy efficiencysomeone2010/11/23 12:42 PM
                              OOOE and energy efficiencyDavid Kanter2010/11/23 06:00 PM
                                OOOE and energy efficiencyajensen2010/11/24 01:58 AM
                                  OOOE and energy efficiencyRichard Cownie2010/11/24 10:44 AM
                                    OOOE and energy efficiencyajensen2010/11/24 01:51 PM
                                      OOOE and energy efficiencyRichard Cownie2010/11/24 02:59 PM
                                        OOOE and energy efficiencyajensen2010/11/25 12:20 AM
                              OOOE and energy efficiencyChuck2010/11/23 10:04 PM
    ISSCC Poulson Preview Online - OoO not unlikely?ajensen2010/11/18 12:48 AM
  ISSCC Poulson Preview OnlineMatt Waldhauer2010/11/17 11:50 AM
    ISSCC Poulson Preview OnlineDavid Kanter2010/11/17 12:21 PM
    ISSCC Poulson Preview Onlinesomeone2010/11/17 12:51 PM
      ISSCC Poulson Preview OnlineMatt Waldhauer2010/11/18 07:38 AM
    ISSCC Poulson Preview OnlineDan Downs2010/11/18 10:15 AM
      ISSCC Poulson Preview OnlineMatt Waldhauer2010/11/23 03:19 AM
  OoOE IPFajensen2010/11/22 02:12 AM
    OoOE IPFanon2010/11/22 03:24 AM
      OoOE IPFajensen2010/11/22 03:46 AM
  ISSCC Poulson Preview Online- Abstractlubemark2010/11/22 08:02 AM
    ISSCC Poulson Preview Online- AbstractIntelUser20002010/11/22 09:49 AM
      ISSCC Poulson Preview Online- AbstractDavid Kanter2010/11/22 11:08 AM
      Cache sharingPaul A. Clayton2010/11/22 01:42 PM
  ISSCC Poulson Preview OnlineTwelve2011/03/23 01:32 PM
    ISSCC Poulson Preview OnlineDaniel Bizó2011/03/24 06:23 AM
Reply to this Topic
Name:
Email:
Topic:
Body: No Text
How do you spell green?