SPEC CPU2006 Cont: Per-Core Performance w/SMT

Moving beyond single-threaded performance, multi-threaded performance within the confines of a single core is of course also important. The Vulcan CPU architecture was designed from the start to leverage SMT4 to keep its cores occupied and boost their overall throughput, so this is where we'll look next.

SPEC CPU2006: Single Core w/SMT
Subtest
SPEC CPU2006
Integer
Application Type Cavium
ThunderX
2 GHz
gcc 5.2
1 thread
Cavium
ThunderX2
@2.5 GHz
gcc 7.2
4 threads
Xeon
8176
@3.8 GHz
gcc 7.2
2 threads
Thunder
X2
vs
Xeon 8176
Thunder
X2
vs
ThunderX
400.perlbench Spam filter 8.3 24.1 50.6 48% 290%
401.bzip2 Compression 6.5 22.9 31.9 72% 350%
403.gcc Compiling 10.8 35 38.1 92% 330%
429.mcf Vehicle scheduling 10.2 52.4 50.6 104% 510%
445.gobmk Game AI 9.2 25.1 35.6 71% 270%
456.hmmer Protein seq. analyses 4.8 26.7 41 65% 560%
458.sjeng Chess 8.8 22.4 37.1 60% 250%
462.libquantum Quantum sim 5.8 83.6 83.2 100% 1440%
464.h264ref Video encoding 11.9 34 66.8 51% 290%
471.omnetpp Network sim 7.3 31.1 41.1 76% 440%
473.astar Pathfinding 7.9 27.2 33.8 80% 340%
483.xalancbmk XML processing 8.4 33.8 75.3 45% 400%

First of all, the ThunderX2 core is a massive improvement over the simple ThunderX core. Even excluding libquantum – that benchmark could easily run 3 times faster on the older ThunderX core after some optimization and compiler improvements – the new ThunderX2 is no less than 3.7 times faster than its older brother. This kind of an IPC advantage makes the original ThunderX's 50% core advantage all but irrelevant.

Looking at the impact of SMT, on average, we see that 4-way SMT improves the ThunderX2's performance by 32%. This ranges from 8% for video encoding to 74% for pathfinding. Intel meanwhile gets a 18% boost from their 2-way SMT, ranging from 4% to 37% in the same respective scenarios.

Overall, a boost of 32% for the ThunderX2 is decent. But it does invite an obvious comparison: how does it fare relative to another SMT4 architecture? Looking at IBM's POWER8, which also supports SMT4, at first glance there seems to be some room for improvement, as the POWER8 sees a 76% boost in the same scenario.

However this isn't entirely an apples-to-apples comparison, as the IBM chip had a much wider back-end: it could issue 10 instructions while the ThunderX2 core is limited to 6 instructions per cycle. The POWER8 core was also much more power hungry: it could fit only 10 of those ultra-wide cores inside a 190W power budget on a 22 nm process. In other words, further increasing the performance gains from using SMT4 would likely require even wider cores, and in turn seriously impact the total number of cores available inside the ThunderX2. Still, it is interesting to put that 32% number into perspective.

Single-Threaded Integer Performance: SPEC CPU2006 Java Performance
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  • imaheadcase - Wednesday, May 23, 2018 - link

    I really think Anandtech needs to branch into different websites. Its very strange and unappealing to certain users to have business/consumer/random reviews/phone info all bunched together.

    Ever since anand actually left it really did venture into more a business/insider based website with random stuff thrown in. It is in no way a bad thing, its just like this review for instance would not appeal to %95 of readers normally. Everyone likes technology naturally that comes to this website, but its a fine line between talking about high end server components that are out of reach to people who just read the article on the mini-itx gaming motherboard. lol
  • Andrei Frumusanu - Wednesday, May 23, 2018 - link

    You're always free to skip articles, nobody's forcing you to read it.
  • boeush - Wednesday, May 23, 2018 - link

    I guess he'd prefer the site content to be grouped in some manner roughly mirroring market segmentation. For instance: consumer, professional, enterprise, exotic/HPC. As opposed to jumbling everything together. Personally, I don't mind - but then, I'm not known for obsessive-compulsive organizing, either :)
  • BurntMyBacon - Thursday, May 24, 2018 - link

    Given the large differences in tech, focus, needs, and trends, I wouldn't mind breaking out Phones and perhaps servers into their own sections. I think there is more than enough overlap to keep consumer and professional desktop/laptop/workstation together, but that is entirely up to how deeply you want to divide things up. On the other hand, you'll want all of it to show up on the front page in some form, or it'll look like the site doesn't have much activity. Perhaps separate pipelines for each category could work. That all said, I don't really mind just skipping over articles that don't interest me. :)
  • imaheadcase - Thursday, May 24, 2018 - link

    Please, that is just lazy excuse. Even news websites have catagory based on the news you interested in. Anandtech literally had a review of a gaming motherboard then a high end server thing, and newz feed gets filled with phone and other news.
  • name99 - Thursday, May 24, 2018 - link

    God, you must REALLY hate Twitter then...

    I argue with Andrei a lot, but every so often he writes a sentence like "You're always free to skip articles, nobody's forcing you to read it" that makes me want to clap him on the back and say "yes, YOU get it" :-)
  • Threska - Sunday, May 27, 2018 - link

    Taken to it's logical extreme the front page could be a dumping ground cesspool and the retort would be "you don't have to wade through any of it" which sounds witty but doesn't solve anything, but over time would lead to the predictable outcome of people leaving.
  • imaheadcase - Sunday, May 27, 2018 - link

    I do hate twitter, but because it has no valid purpose other than to get customer service done faster with companies because it reflects more on them because public venue. Its mostly just a rant inducing place, or a place that is basically just texting anyways since everyone just wants you to send a DM.

    The whole idea of saying "you are free to skip it" is kinda silly thing to say on the internet now. Especially since more and more you can filter things according to what you want. Not only that, but with the tight competition with views from tech websites its in best interest to have more options.

    Even the layout of website never changed. I mean have you ever been to website without a adblocker on? They don't even advertise tech related stuff on it. Its just stupid clickbait stuff.

    Keep in mind, this is not a complaint about articles itself, its just how they are posted. I love this site, been coming to it ever since i built first pc when i was a kid. But its focus is all over the place now vs years ago out what its posting. I'm half thinking one day i will see a review of electronic toothbrush then next day new CPU.
  • GreenReaper - Monday, June 4, 2018 - link

    I'd be fine with that, as long as it was the best darn toothbrush in town!
  • Threska - Sunday, May 27, 2018 - link

    Accessing through RSS might be a better solution especially with a good reader. Just needs accurate tags to match.

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