industry-standard single-threaded performance benchmarks absent

By: anon (anon.delete@this.anon.com), February 9, 2010 10:21 am
Room: Moderated Discussions
Linus Torvalds (torvalds@linux-foundation.org) on 2/9/10 wrote:
---------------------------
>Michael S (already5chosen@yahoo.com) on 2/9/10 wrote:
>>
>>Unfortunately, due to autopar, Nehalem (and SPARC64)
>>SpecInt2k6 scores have very remote relationship to single-
>>threaded performance. SpecInt as a measure of single-
>>threaded performance is now defunct and we should look for
>>something else.
>>Now what's the chance that we'll find the same "something
>>else" for both Nehalem and POWER7? I'd say, close to zero.
>
>Actually, not really.
>
>There's one easy way to make SpecInt2006 relevant, with
>no changes what-so-ever.
>
>Go to the spec site, and instead of asking for the baseline
>and result numbers, just query by 403.gcc instead. Voila!
>You now have meaningful and comparable results.
>
>That's actually been true for at least the last two decades.
>Nobody has ever broken gcc as a benchmark, and it continues
>to be the one benchmark that actually gives a good view of
>real-life integer performance.
>
>Almost everything else is about small snippets of code
>that can be optimized to hell and back.
>
>And btw, Nehalem does very well on 403.gcc too. So while
>things like libquantum have been broken, it doesn't at all
>invalidate the fact that Nehalem is (and likely remains)
>the absolute king of single-threaded integer performance.

POWER7 has a turbo mode too when 4 cores or fewer are running it apparently can reach as high as 4.1GHz. In specjbb, a reasonable integer test, although it is a throughput test, top comparable 4 core Nehalem can't quite reach 3.55GHz POWER7 per-core.

Yes Nehalem's turbo mode for single thread is quite large. And yes it is extrapolating single thread performance from throughput test.

But also it is just your conjecture that POWER7 will be relatively worse in single threaded -- POWER5 had an average gain of 20% for SMT-2 so I would be surprised if POWER7 is more than 30% for SMT-4.

>
>By a big margin, too. Nehalem beats POWER6 at 4.7GHz by
>more than 50%, for example (32.1/30.2. vs 20.6/16.8 - and
>POWER6 in turn beats Itanium by almost doubling the
>performance of that crap).
>
>So if POWER7 comes close that is kind of a big deal. Intel
>has been so far ahead on those things that it's
>not even funny.

POWER7 should definitely be close. Maybe even ahead.
< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
POWER7 SpecParadox2010/02/08 11:05 AM
  POWER7 SpecThu Nguyen2010/02/08 12:58 PM
    POWER7 SpecIan Ameline2010/02/08 09:22 PM
      POWER7 SpecThu Nguyen2010/02/08 11:54 PM
        POWER7 SpecIan Ameline2010/02/09 06:46 AM
          POWER7 SpecLinus Torvalds2010/02/09 07:57 AM
            industry-standard single-threaded performance benchmarks absentMichael S2010/02/09 08:09 AM
              industry-standard single-threaded performance benchmarks absentParadox2010/02/09 08:33 AM
                industry-standard single-threaded performance benchmarks absentMichael S2010/02/09 09:30 AM
                  industry-standard single-threaded performance benchmarks absentParadox2010/02/09 10:52 AM
                    industry-standard single-threaded performance benchmarks absentJesper Frimann2010/02/09 11:33 AM
              industry-standard single-threaded performance benchmarks absentLinus Torvalds2010/02/09 08:48 AM
                industry-standard single-threaded performance benchmarks absentMichael S2010/02/09 09:26 AM
                  industry-standard single-threaded performance benchmarks absentLinus Torvalds2010/02/09 09:58 AM
                    industry-standard single-threaded performance benchmarks absentJesper Frimann2010/02/09 12:17 PM
                      industry-standard single-threaded performance benchmarks absentLinus Torvalds2010/02/09 12:54 PM
                        industry-standard single-threaded performance benchmarks absentJesper Frimann2010/02/09 02:10 PM
                    industry-standard single-threaded performance benchmarks absentParadox2010/02/09 01:22 PM
                industry-standard single-threaded performance benchmarks absentanon2010/02/09 10:21 AM
            POWER7 SpecJesper Frimann2010/02/09 12:30 PM
            POWER7 SpecDoug Siebert2010/02/09 05:38 PM
              POWER7 SpecLinus Torvalds2010/02/09 07:28 PM
                POWER7 SpecLinus Torvalds2010/02/09 07:28 PM
                  POWER7 SpecIan Ameline2010/02/09 08:02 PM
                    POWER7 SpecDoug Siebert2010/02/09 10:18 PM
                POWER7 Specsomeone2010/02/09 08:20 PM
                  POWER7 SpecLinus Torvalds2010/02/10 09:17 AM
                    POWER7 SpecLinus Torvalds2010/02/10 09:46 AM
                      POWER7 SpecEmil2010/02/10 11:06 AM
                    POWER7 SpecIan Ameline2010/02/10 10:13 AM
                    POWER7 Specsomeone2010/02/10 11:01 AM
                      POWER7 SpecLinus Torvalds2010/02/10 11:32 AM
                        POWER7 SpecMichael S2010/02/10 12:30 PM
                          POWER7 SpecLinus Torvalds2010/02/10 01:25 PM
                            POWER7 Specmpx2010/02/10 02:58 PM
                        POWER7 Specnemlis2010/02/11 12:24 AM
                          POWER7 Specnone2010/02/11 12:52 AM
                            POWER7 Specnemlis2010/02/11 01:52 PM
          POWER7 Specmpx2010/02/09 08:18 AM
          POWER7 SpecMichael S2010/02/09 09:08 AM
        POWER7 SpecJesper Frimann2010/02/16 02:29 AM
          POWER7 SpecJamie Lucier2010/02/16 06:35 AM
            POWER7 Specanon2010/02/16 07:16 AM
              POWER7 SpecJamie Lucier2010/02/16 10:46 AM
                POWER7 Specanon2010/02/16 03:42 PM
                  POWER7 SpecJamie Lucier2010/02/18 06:07 AM
              POWER7 SpecThu Nguyen2010/02/16 01:23 PM
            POWER7 SpecParadox2010/02/16 09:57 AM
              POWER7 SpecJamie Lucier2010/02/16 11:22 AM
                POWER7 SpecParadox2010/02/16 02:00 PM
            POWER7 SpecJesper Frimann2010/02/16 02:14 PM
              POWER7 SpecJamie Lucier2010/02/17 10:41 AM
  POWER7 SpecJesper Frimann2010/02/09 04:43 AM
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