SMT Integer Performance With SPEC CPU2006

Next, to test the performance impact of simultaneous multithreading (SMT) on a single core, we test with two threads on the same core. This way we can evaluate how well the core handles SMT. 

Subtest Application type Xeon E5-2690 @ 3.8 Xeon E5-2690 v3 @ 3.5 Xeon E5-2699 v4 @ 3.6 EPYC 7601 @3.2 Xeon 8176 @ 3.8
400.perlbench Spam filter 39.8 43.9 47.2 40.6 55.2
401.bzip2 Compression 32.6 32.3 32.8 33.9 34.8
403.gcc Compiling 40.7 43.8 32.5 41.6 32.1
429.mcf Vehicle scheduling 44.7 51.3 55.8 44.2 56.6
445.gobmk Game AI 36.6 35.9 38.1 36.4 39.4
456.hmmer Protein seq. analyses 32.5 34.1 40.9 34.9 44.3
458.sjeng Chess 36.4 36.9 39.5 36 41.9
462.libquantum Quantum sim 75 73.4 89 89.2 91.7
464.h264ref Video encoding 52.4 58.2 58.5 56.1 75.3
471.omnetpp Network sim 25.4 30.4 48.5 26.6 42.1
473.astar Pathfinding 31.4 33.6 36.6 29 37.5
483.xalancbmk XML processing 43.7 53.7 78.2 37.8 78

Now on a percentage basis versus the single-threaded results, so that we can see how much performance we gained from enabling SMT:

Subtest Application type Xeon E5-2699 v4 @ 3.6 EPYC 7601 @3.2 Xeon 8176 @ 3.8
400.perlbench Spam filter 109% 131% 110%
401.bzip2 Compression 137% 141% 128%
403.gcc Compiling 137% 119% 131%
429.mcf Vehicle scheduling 125% 110% 131%
445.gobmk Game AI 125% 150% 127%
456.hmmer Protein seq. analyses 127% 125% 125%
458.sjeng Chess 120% 151% 125%
462.libquantum Quantum sim 91% 129% 90%
464.h264ref Video encoding 101% 112% 112%
471.omnetpp Network sim 109% 116% 103%
473.astar Pathfinding 140% 149% 137%
483.xalancbmk XML processing 120% 107% 116%

On average, both Xeons pick up about 20% due to SMT (Hyperthreading). The EPYC 7601 improved by even more: it gets a 28% boost on average. There are many possible explanations for this, but two are the most likely. In the situation where AMD's single threaded IPC is very low because it is waiting on the high latency of a further away L3-cache (>8 MB), a second thread makes sure that the CPU resources can be put to better use (like compression, the network sim). Secondly, we saw that AMD core is capable of extracting more memory bandwidth in lightly threaded scenarios. This might help in the benchmarks that stress the DRAM (like video encoding, quantum sim). 

Nevertheless, kudos to the AMD engineers. Their first SMT implementation is very well done and offers a tangible throughput increase. 

Single Threaded Integer Performance: SPEC CPU2006 Multi-core SPEC CPU2006
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  • ddriver - Tuesday, July 11, 2017 - link

    Gotta love the "you don't care about the xeon prices" part thou. Now that intel don't have a performance advantage, and their product value at the high end is half that of amd, AT plays the "intel is the better brand" card. So expected... Reply
  • OZRN - Wednesday, July 12, 2017 - link

    You need some perspective. Database licensing for Oracle happens per core, where Intel's performance is frequently better in a straight line and since they achieve it on lower core count it's actually better value for the use case. Higher per-CPU cost is not so much of a concern when you pay twice as much for a processor license to cover those cores.

    I'm an AMD fan and I made this account just for you, sweetheart, but don't blind yourself to the truth just because Intel has a history of shady business. In most regards this is a balanced review, and where it isn't, they tell you why it might not be. Chill out.
    Reply
  • ddriver - Thursday, July 13, 2017 - link

    You are such a clown. Nobody, I repeat, NOBODY on this planet uses 64 core 128 thread 512 gigabytes of ram servers to run a few MB worth of database. You telling me to get pespective thus can mean only two things, that you are a buthurt intel fanboy troll or that you are in serious need of head examination. Or maybe even both. At any rate, that perfectly explains your ridiculously low standards for "balanced review". Reply
  • Notmyusualid - Friday, July 14, 2017 - link

    It seems no matter what opinion someone presents that might exhibit Intel in a better light - you are going to hate it anyway.

    What a life you must lead.
    Reply
  • OZRN - Friday, July 14, 2017 - link

    No, they don't. They use them to host gigabytes to terabytes worth of mission critical databases, with specified amounts of cores dedicated to seperate environments of hard partitioned data manipulation. I've done some quick math for you and in an average setup of Enterprise Edition of Oracle DB, with only the usually reported options and extras, this type of database would cost over $3.7m to run on *64 cores alone*. At this point, where is your hardware sunk costs argument?

    Also, I don't think anyone here is impressed by your ability to immediately personally insult people making valid points. Good luck finding your head that deep in your colon.
    Reply
  • CajunArson - Tuesday, July 11, 2017 - link

    "All of our testing was conducted on Ubuntu Server "Xenial" 16.04.2 LTS (Linux kernel 4.4.0 64 bit). The compiler that ships with this distribution is GCC 5.4.0."

    I'd recommend using a more updated distro and especially a more up to date compiler (GCC 5.4 is only a bug-fix release of a compiler from *2015*) if you want to see what these parts are truly capable of.

    Phoronix does heavy-duty Linux reviews and got some major performance boosts on the i9 7900X simply by using up to date distros: http://www.phoronix.com/scan.php?page=article&...

    Considering that Purley is just an upscaled version of the i9 7900X, I wouldn't be surprised to see different results.
    Reply
  • CajunArson - Tuesday, July 11, 2017 - link

    As a followup to my earlier comment, that Phoronix story, for example, shows a speedup factor of almost 5X on the C-ray benchmark simply by using a modern distro with some tuning for the more modern Skylake architecture.

    I'm not saying Purley would have a 5X speedup on C-ray per-say, but I'd be shocked if it didn't get a good boost using modern software that's actually designed for the Skylake architecture.
    Reply
  • CoachAub - Wednesday, July 12, 2017 - link

    Keywords: "actually designed for the Skylake architecture". Will there be optimizations for AMD Epyc chips? Reply
  • mkozakewich - Friday, July 14, 2017 - link

    If it's a reasonable optimization, it makes sense to include it in the benchmark. If I were building these systems, I'd want to see benchmarks that resembled as closely as possible my company's workflow. (Which may be for older software or newer software; neither are inherently more relevant, though benchmarks on newer software will usually be relevant further into the future.) Reply
  • CajunArson - Tuesday, July 11, 2017 - link

    And another followup: The time kernel compilation on the i9 7900X got almost a factor of 2 speedup over the Ubuntu 16.04 using more modern distros. Reply

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