SPEC is NOT a representation of average workloads

By: Chester (lamchester.delete@this.gmil.com), November 18, 2020 2:13 pm
Room: Moderated Discussions
Andrei F (andrei.delete@this.anandtech.com) on November 18, 2020 7:44 am wrote:
> Chester (lamchester.delete@this.gmail.com) on November 18, 2020 7:02 am wrote:
>
> > Sure, Cinebench isn't the best representation of average workloads. But SPEC is far
> > worse. No consumer cares about SPEC. The subtests are mostly based off applications
> > no one uses, or very specific scientific simulations. It's even useless as a benchmark
> > to see whether your system is working properly, because it's so overpriced.
> >
> > Even when they base a subtest off something a consumer might
> > do, the results are hilariously off. For example:
> > Encoding a 4K video using ffmpeg libx264 slow preset, on Haswell locked to 2.2 GHz
> > - affinity set to 4 threads: 6.6 fps
> > - no affinity set: 7.6 fps (1.15x scaling)
> >
> > 525.x264_r test: 1.0315x scaling
> >
> > A quick look at the benchmark description shows them using -bitrate 1000.
> > If that's 1 kbps (or 1 mbps) bitrate, it's hilariously unrealistic.
> >
> > Now take AT Bench's POV-Ray scores for the i5-6600K (1741, 3.6 GHz all core turbo)
> > and i7-6700K (2419, 4.2 GHz all core turbo). Scaling down the 6700K's score to account
> > for clock speed difference gives 2073. SMT scaling would be roughly 1.19x
> >
> > 511.povray_r: 1.0291x scaling.
> >
> > What's going on?
> >
> > Also, some SPEC numbers make it seem like negative SMT scaling is common. It's not. I've
> > personally never seen an application that can use all available threads do worse when
> > SMT is enabled. Can we stop looking at the irrelevant pile of garbage that is SPEC?
> >
> > And what makes you claim "Cinebench has long dependency chains"? How do you
> > know SMT scaling is from that rather than hiding cache misses better?
>
> Because Maxon developers *literally told us that*. There's apparently
> a lot of random accesses to the BVH of the scene.

So to be more specific, it's memory latency, not execution latency. That I can believe - Zen 2 almost never stalls rename bc the FP scheduler's full. However, the AGSQ does fill (~14.2% of cycles).

> The CB23 score on the M1 goes from 5601 to to 7819 when comparing just the big cores to having
> both the big and small cores together. Explain to me how that happens that the SoC gets 39% more
> throughput from cores that are 1/4th the performance? It's an extreme showcase of a dependency
> workload that scales extremely well with threads - again, straight from the Maxon devs.

Is it an 'extreme showcase of a dependency workload'? For starters it sounds like this applies to all raytracing workloads. And being limited by cache latency isn't exactly rare.
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TopicPosted ByDate
1st round of M1 GPU benchmarksMaynard Handley2020/11/16 12:46 PM
  1st round of M1 GPU benchmarksAdrian2020/11/16 01:02 PM
    1st round of M1 GPU benchmarksI_vs2020/11/17 01:18 AM
  1st round of M1 GPU benchmarksRType2020/11/16 01:06 PM
    1st round of M1 GPU benchmarksMaynard Handley2020/11/16 01:45 PM
      And the NZ'ers are first to deliver cinebench scoresMaynard Handley2020/11/16 02:58 PM
        And the NZ'ers are first to deliver cinebench scoresWill2020/11/16 03:30 PM
          re: "scaling"Dummond D. Slow2020/11/16 04:06 PM
            re: "scaling"Maynard Handley2020/11/16 04:29 PM
              re: "scaling"Dummond D. Slow2020/11/16 04:51 PM
                re: "scaling"Maynard Handley2020/11/16 05:51 PM
                  re: "scaling"Dummond D. Slow2020/11/16 06:22 PM
                    re: "scaling"Maynard Handley2020/11/16 06:23 PM
                      re: "scaling"Maynard Handley2020/11/16 06:27 PM
                        re: "scaling"Dummond D. Slow2020/11/16 06:37 PM
                          re: "scaling"Chester2020/11/16 08:25 PM
                          Actual power consumption values.Dummond D. Slow2020/11/17 07:05 AM
                    re: "scaling"Doug S2020/11/17 10:25 AM
                      Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/17 11:18 AM
                        Apple loses a lot by not having turbo and SMTDoug S2020/11/17 12:21 PM
                          Apple loses a lot by not having turbo and SMTblaine2020/11/19 05:18 PM
                            Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/19 05:31 PM
                        Apple loses a lot by not having turbo and SMTTJ2020/11/18 01:10 AM
                          Cinebench is NOT a representation of average workloadsAndrei F2020/11/18 05:21 AM
                            SPEC is NOT a representation of average workloadsChester2020/11/18 07:02 AM
                              SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 07:17 AM
                                SPEC is NOT a representation of average workloadsnone2020/11/18 08:18 AM
                                  x264 without SIMD is nonsenseDummond D. Slow2020/11/18 08:31 AM
                                  SPEC is NOT a representation of average workloadsMaynard Handley2020/11/18 09:13 AM
                                    SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 09:21 AM
                                      SPEC is NOT a representation of average workloadsWilco2020/11/18 09:42 AM
                                        role of hand-optimized assembly in multimedia encodersDummond D. Slow2020/11/18 11:06 AM
                                          role of hand-optimized assembly in multimedia encodersdifferent anon2020/11/18 01:27 PM
                                            role of hand-optimized assembly in multimedia encodersDummond D. Slow2020/11/18 02:47 PM
                                              role of hand-optimized assembly in multimedia encodersDummond D. Slow2021/05/18 12:29 PM
                                          role of hand-optimized assembly in multimedia encodersRichardC2020/11/18 03:42 PM
                                          role of hand-optimized assembly in multimedia encodersnone2020/11/19 07:17 AM
                                      SPEC is NOT a representation of average workloadsnone2020/11/18 10:14 AM
                                        SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 11:17 AM
                                      SPEC is NOT a representation of average workloadsMaynard Handley2020/11/18 11:03 AM
                                        SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 11:25 AM
                                          SPEC is NOT a representation of average workloadsMaynard Handley2020/11/18 12:03 PM
                                            SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 02:57 PM
                                              SPEC is NOT a representation of average workloadsMaynard Handley2020/11/18 04:36 PM
                                                SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 04:50 PM
                                                  SPEC is NOT a representation of average workloadsDoug S2020/11/19 09:13 AM
                                                    SPEC is NOT a representation of average workloads-.-2020/11/19 02:34 PM
                                                    SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/19 02:35 PM
                                              SPEC is NOT a representation of average workloadsEtienne Lorrain2020/11/19 04:04 AM
                                                SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/19 05:58 AM
                                SPEC is NOT a representation of average workloadsChester2020/11/18 02:06 PM
                                  about bitratesDummond D. Slow2020/11/18 03:04 PM
                                    about bitratesChester2020/11/19 02:45 PM
                                  SPEC is NOT a representation of average workloadsOok2020/11/18 03:05 PM
                                    SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 03:21 PM
                                  SPEC is NOT a representation of average workloadsNoSpammer2020/11/19 06:48 AM
                              SPEC is NOT a representation of average workloadsAndrei F2020/11/18 07:44 AM
                                SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 07:48 AM
                                  SPEC is NOT a representation of average workloadsAdrian2020/11/18 08:15 AM
                                    SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 08:41 AM
                                      SPEC is NOT a representation of average workloadsAdrian2020/11/18 09:04 AM
                                        SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 09:32 AM
                                          SPEC is NOT a representation of average workloadsAdrian2020/11/18 10:26 AM
                                    SPEC is NOT a representation of average workloadsMaynard Handley2020/11/18 09:22 AM
                                      SPEC is NOT a representation of average workloadsAdrian2020/11/18 10:28 AM
                                  SPEC is NOT a representation of average workloadsAndrei F2020/11/18 08:34 AM
                                    SPEC is NOT a representation of average workloadsDummond D. Slow2020/11/18 09:00 AM
                                    SPEC is NOT a representation of average workloadsChester2020/11/18 02:18 PM
                                    SPEC is NOT a representation of average workloadsJukka Larja2020/11/20 08:03 AM
                                SPEC is NOT a representation of average workloadsChester2020/11/18 02:13 PM
                              SPEC is NOT a representation of average workloadsnone2020/11/18 08:07 AM
                                SPEC is NOT a representation of average workloadsMichael S2020/11/18 01:33 PM
                                  Interesting, thanks! (NT)none2020/11/19 07:03 AM
                            Cinebench is NOT a representation of average workloadsrwessel2020/11/18 07:03 AM
                              Cinebench is NOT a representation of average workloadsDoug S2020/11/18 07:44 AM
                                Cinebench is NOT a representation of average workloadsDummond D. Slow2020/11/18 07:52 AM
                                  Cinebench is NOT a representation of average workloadsDoug S2020/11/18 02:59 PM
                                    Cinebench is NOT a representation of average workloadsDummond D. Slow2020/11/18 03:12 PM
                                      Cinebench is NOT a representation of average workloadsDoug S2020/11/19 09:19 AM
                                        Cinebench is NOT a representation of average workloadsDummond D. Slow2020/11/19 03:03 PM
                                          Cinebench is NOT a representation of average workloadsUngo2020/11/19 08:12 PM
                                            Cinebench is NOT a representation of average workloadsDummond D. Slow2020/11/20 08:45 AM
                                It's not really SMT or adding small coresDummond D. Slow2020/11/18 07:58 AM
                                  It's not really SMT or adding small coresDoug S2020/11/18 03:02 PM
                                    It's not really SMT or adding small coresDummond D. Slow2020/11/18 03:27 PM
                                Cinebench is NOT a representation of average workloadsxyz2020/11/18 12:14 PM
                                  Cinebench is NOT a representation of average workloadsMaynard Handley2020/11/18 12:54 PM
                                    Cinebench is NOT a representation of average workloadsGabriele Svelto2020/11/18 01:41 PM
                                      Cinebench is NOT a representation of average workloadsMaynard Handley2020/11/18 01:52 PM
                                        Cinebench is NOT a representation of average workloadsGabriele Svelto2020/11/18 02:05 PM
                            Cinebench is NOT a representation of average workloadsTJ2020/11/18 11:46 AM
                            SMT shines in IO heavy & commercial DB workloadsxyz2020/11/18 12:05 PM
                            "Average workloads" don't exist (NT)Foo_2020/11/19 02:55 AM
                          Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/18 07:02 AM
                            Apple loses a lot by not having turbo and SMTMaynard Handley2020/11/18 08:37 AM
                              Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/18 08:55 AM
                              Apple loses a lot by not having turbo and SMTDavid Hess2020/11/18 12:12 PM
                                Apple loses a lot by not having turbo and SMTMaynard Handley2020/11/18 01:12 PM
                                  Apple loses a lot by not having turbo and SMTJörn Engel2020/11/18 04:04 PM
                                    Apple loses a lot by not having turbo and SMTanonymou52020/11/18 04:37 PM
                                      Apple loses a lot by not having turbo and SMTJörn Engel2020/11/19 03:28 AM
                                  Apple loses a lot by not having turbo and SMTDavid Hess'2020/11/19 06:25 PM
                          Apple loses a lot by not having turbo and SMTAdrian2020/11/18 07:23 AM
                            Apple loses a lot by not having turbo and SMTgallier22020/11/18 11:21 PM
                              Apple loses a lot by not having turbo and SMTJames2020/11/19 01:22 AM
                                Apple loses a lot by not having turbo and SMTWilco2020/11/19 04:06 AM
                              Apple loses a lot by not having turbo and SMTanonymou52020/11/19 01:34 AM
                                Apple loses a lot by not having turbo and SMTgallier22020/11/19 08:04 AM
                                  big.LITTLE with different ISAsJames2020/11/19 08:41 AM
                                    big.LITTLE with different ISAsgallier22020/11/20 02:36 AM
                                    big.LITTLE with different ISAsanon2020/11/20 12:31 PM
                              Apple loses a lot by not having turbo and SMTAdrian2020/11/19 01:56 AM
                        Apple loses a lot by not having turbo and SMTJon Masters2020/11/18 11:46 AM
                          Apple loses a lot by not having turbo and SMTanonymou52020/11/18 02:41 PM
                          Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/18 03:17 PM
                            Apple loses a lot by not having turbo and SMTMaynard Handley2020/11/18 04:46 PM
                              Apple loses a lot by not having turbo and SMTJon Masters2020/11/18 11:31 PM
                                Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/19 06:01 AM
                              Apple loses a lot by not having turbo and SMTAdrian2020/11/19 01:50 AM
                                Apple loses a lot by not having turbo and SMTAdrian2020/11/19 02:10 AM
                                Apple loses a lot by not having turbo and SMTMaynard Handley2020/11/19 09:13 AM
                                  Apple loses a lot by not having turbo and SMTDummond D. Slow2020/11/19 03:10 PM
                        Apple loses a lot by not having turbo and SMTjuanrga2020/11/19 01:49 AM
                    re: "scaling"sr2020/11/17 11:39 AM
                      re: "scaling"Adrian2020/11/17 12:41 PM
                        re: "scaling"Adrian2020/11/17 12:52 PM
                          re: "scaling"Chester2020/11/17 05:29 PM
                  re: "scaling"anonymou52020/11/16 07:18 PM
                    re: "scaling"Maynard Handley2020/11/16 07:44 PM
        And the NZ'ers are first to deliver cinebench scoresDummond D. Slow2020/11/16 04:12 PM
          And the NZ'ers are first to deliver cinebench scoresMaynard Handley2020/11/16 04:31 PM
            And the NZ'ers are first to deliver cinebench scoresDummond D. Slow2020/11/16 04:46 PM
        And the NZ'ers are first to deliver cinebench scoresMaynard Handley2020/11/16 06:04 PM
          And the NZ'ers are first to deliver cinebench scoresDummond D. Slow2020/11/16 06:28 PM
  1st round of M1 GPU benchmarksRayla2020/11/16 03:16 PM
    1st round of M1 GPU benchmarksChester2020/11/16 08:17 PM
  Phoronix Mac mini M1 benchanon52020/11/20 10:51 AM
    Phoronix Mac mini M1 benchPer Hesselgren2020/11/24 09:04 AM
      Phoronix Mac mini M1 benchPaul2020/11/25 02:08 AM
        Phoronix Mac mini M1 benchPaul2020/11/25 02:12 AM
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