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  • eSyr - Wednesday, June 3, 2020 - link

    "8-wide decode core, which as far as we know would have been the widest commercial microarchitecture that we know of" — POWER 8 has 8-wide decode, you have written about it in 2016[1].

    [1] https://www.anandtech.com/show/10435/assessing-ibm...
  • Tabalan - Wednesday, June 3, 2020 - link

    I think POWER8 is purely professional product, while M6 core would be installed in purely commercial devices (Galaxy S30, Note 30). At least that's my point of view.
  • eSyr - Wednesday, June 3, 2020 - link

    What do you mean by "commercial devices"? Those which sell freely? One can buy a POWER machine the same way one can buy a Samsung device, on the Internet[1][2][3].

    [1] https://www.raptorcs.com/TALOSII/
    [2] https://www.alancomputech.com/cpus-other-cpus.html
    [3] https://www.amazon.com/dp/B077T2WMGD
  • Tabalan - Wednesday, June 3, 2020 - link

    1st link are rack units/workstations and 3rd link is server rack unit on Intel Xeon. I'd say commercial - professional is more about purpose. With Nvidia you have GTX/RTX for commercial use and Tesla/Quadro for professional use. Pretty much same with many tech companies, like AMD, Intel, Samsung,...
  • cjl - Wednesday, June 3, 2020 - link

    Professional is still commercial. The only non-commercial stuff out there would be military/government/etc. A more accurate term for what you're looking for is consumer.
  • soresu - Wednesday, June 3, 2020 - link

    I think they meant consumer rather than commercial, as opposed to pro/server components.
  • Andrei Frumusanu - Wednesday, June 3, 2020 - link

    That's not exactly correct, the POWER8 has a 6+2 or 2x(3+1) decoder, where it the 6/3 would by instruction invariant and the +2/1 would be just branches. In effect Samsung's design here would be wider in terms of being a traditional 8-wide decoder.
  • eSyr - Wednesday, June 24, 2020 - link

    I've missed that aspect of P8 decoder, thank you.
  • dotjaz - Wednesday, June 3, 2020 - link

    8 is not wider than 8 in any case.
  • soresu - Wednesday, June 3, 2020 - link

    Er, Alpha EV8?
  • eSyr - Wednesday, June 24, 2020 - link

    Hm, indeed, thank you for pointing that out. It's unfinished (as well as M6), though.
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  • Lodix - Wednesday, June 3, 2020 - link

    Thanks to Samsung and you for sharing this.
  • willis936 - Wednesday, June 3, 2020 - link

    Wow that table is awesome. I'd love to see a table like that to show the evolution of x86 architectures over the past 20 years.
  • shabby - Wednesday, June 3, 2020 - link

    Intel: 5% ipc increase year over year due to 5% clock increase...
  • incx - Wednesday, June 3, 2020 - link

    IPC - instructions per clock. E.g. IPC increases cannot really be due to clock speed increases.
  • dotjaz - Wednesday, June 3, 2020 - link

    That's by definition wrong.
  • eastcoast_pete - Wednesday, June 3, 2020 - link

    Thanks for your report on this post-mortem of SARC's Mongoose designs; very interesting! And yes, it's nice that Samsung leadership permitted this. A key take-home for me is in the Q&A part: the design team knew that they were only making incremental changes on a loosing design, but were prevented from making more fundamental changes that might well have made M6 or M7 a lot more competitive. I wonder how much that decision by the powers that be at Samsung was really due to resources (really? One of the largest electronics companies in the World?) , or whether that was to avoid admitting that the road taken had reached its end, and a new direction was needed. It's all hypothetical now, of course, but unfortunate.
  • s.yu - Wednesday, June 3, 2020 - link

    lol, postmortem, I was gonna say it's an obituary.
  • Dolda2000 - Wednesday, June 3, 2020 - link

    To be fair, even though Samsung is a huge company with large resources, that doesn't mean they'd be throwing them around carelessly, and for all we know, the Exynos cores may have very well been a somewhat experimental/peripheral project.
  • eastcoast_pete - Wednesday, June 3, 2020 - link

    I don't think that they (Samsung) threw resources around carelessly; they restricted and then terminated their investment when they might have gone the other way and given SARC the extra means to try for a truly competitive big core. Why? My belief is that Samsung was, at least initially, trying to create a big ARM v8-based core that could compete with Apple's highly successful big cores. As we all know, no stock ARM core has yet come within striking distance to Apple's big custom core of the same year/generation. Having such an actually competitive big core would have helped Samsung to keep its foundries busy regardless of Apple and others sending their business to TSMC, and given their in-house design a significant advantage over QCs Snapdragon SoCs. But, that clearly didn't happen, mongoose never really caught its intended prey.
  • Deicidium369 - Friday, June 12, 2020 - link

    Samsung wrote the book on throwing around resources - they dive head first, almost get stuff working then abandon - this will be the pattern for the license of AMD graphics IP. 1 Generation - never built in large quantities and then shelved - that's the Samsung pattern.
  • yeeeeman - Wednesday, June 3, 2020 - link

    While this line of CPUs will not be remember as something awesome, I still use my Galaxy S7 with the M1 core and it still runs just fine with the usual apps, while lasting at least a day on battery.
  • melgross - Wednesday, June 3, 2020 - link

    Very interesting. All the woulda, shoulda, coulda, doesn’t matter in the end though. What’s also interesting was the statement that Samsung never allocated enough resources for them to do a real redesign. That’s hard to understand. Samsung Electronics is a massive company. They could have surely afforded a couple of hundred million, even yearly, to increase the R&D efforts.

    If they had a truly competitive SoC, they would have been able to compete with Qualcomm on even terms. Why they didn’t is hard to explain, from the outside.

    Meanwhile this talk they gave, while a glimpse into history, offers nothing for current chip designers to get excited about.
  • dotjaz - Wednesday, June 3, 2020 - link

    You simply don't understand ROI, do you? A couple of hundred millions for what in return?
  • Tabalan - Wednesday, June 3, 2020 - link

    Well, Qualcomm earned over 24 bln $ last year and they mainly do in SoC, modems, wireless communication (all areas where Samsung could compete). Also, if Samsung had bleeding edge core, they could use it for server CPU as well. What is more, they could produce their SoC in-house, further increasing profits for Samsung. I'd say there was a lot to gain, too bad Samsung didn't invest more into it.
  • dotjaz - Wednesday, June 3, 2020 - link

    And how much of that revenue was because of a CUSTOM CPU core?
  • lmcd - Thursday, June 4, 2020 - link

    LOL as if Qualcomm's revenue comes from playing on a level playing field. Qualcomm has a custom modem, and until US carriers get turned into a utility no other SoC in the US matters.

    Qualcomm's lack of a custom core, however, should by all rights inhibit them from design wins in Microsoft's Surface X and other Windows on ARM devices. 8cx is trash and an Apple-level of custom CPU core would absolutely annihilate 8cx. Samsung also still makes tablets, which a big core would greatly help them with.
  • dotjaz - Friday, June 5, 2020 - link

    I'm sure you are more successful than both Qualcomm and Samsung.
  • lmcd - Friday, June 12, 2020 - link

    I'm sure you can make pointless statements when your original claim is disputed.
  • melgross - Thursday, June 4, 2020 - link

    The point is that Samsung g has a lot of experience and resources to do that. When Apple announced they were going to design their own, they were ridiculed for it. How would it be possible people asked? But they did it. Samsung could have made the decision to do this the right way, if they wanted to. Asian companies are very conservative. They aren’t willing to take the chances that others do, particularly American companies.

    So Samsung became nervous over the prospect, and chickened out. That what it was.
  • dotjaz - Friday, June 5, 2020 - link

    They took a chance and failed miserably, they are not the only one. Qualcomm failed miserably as well.
  • dotjaz - Wednesday, June 3, 2020 - link

    Also funny you should mention Qualcomm and server cores, remember the hugely successful Centriq? I don't think so.
    Both Amazon and Ampere as well as EPI have switched to Neoverse. The only ones left standing (for now) are Marvell and HiSilicon. And based on current market share and performance, neither are that promising.
  • eastcoast_pete - Wednesday, June 3, 2020 - link

    I believe for the chance to be the king of the performance hill for Android (and maybe Windows on ARM), with performance similar to Apple's big cores. But yes, that didn't exactly happen. However, sometimes you have to invest at risk if you're after big rewards.
  • melgross - Thursday, June 4, 2020 - link

    Maybe you don’t. I understand it very well. Samsung Electronics is a company with over $200 billion in sales. You apparently don’t know that. They spend close to $20 billion a year on R&D. I guess you don’t know that either. If they really wanted to selol their SoCs to others, the way they did to Apple for a few years, they needed to up their game. Apple was, according to reports, 40% of their SoC production in dollars. That was a major loss, and shook the company. The fact is that they went the wrong way with their designs. They needed to, as they admitted, redesign a fair amount of it from scratch.

    They could have done that if they decided to spend just a bit more. But upper management decided instead to retrench, and give up on the possibility of really competing with Qualcomm and others. We’ll never know what could have happened now. This presentation was that of a failed design, nothing more.
  • anonomouse - Wednesday, June 3, 2020 - link

    It's not like they had infinite engineers they could go hire even if they wanted to, and adding more engineers doesn't mean a linear increase in productivity either. They made it clear how important schedule was for them. An aggressive yearly update cadence certainly would have made large, ambitious changes or clean reimplementations quite risky. It's like they said, they couldn't ever afford to miss the product schedule for the phone, so they probably just ended up stuck with a bunch of suboptimal early choices that they couldn't really fix. I mean, look at size, width and depth they're talking about in M6 and compare that with similar or worse performance wrt A77, which is much smaller, narrower, and shallower. Or compare to Apple, which doesn't explicitly disclose any of these things, but there are no clearly indications that it is substantially larger in any particular dimension (except caching in the further parts of the memory subsystem), and yet has vastly superior IPC. Clearly there must be a lot of issues all over the place that they just never could get around to fixing.
  • WJMazepas - Wednesday, June 3, 2020 - link

    What i dont get it is why Samsung invested in the M Cores. They didnt funded they enough. Was not better then just license the ARM IP? It probably would be cheaper
  • jeremyshaw - Wednesday, June 3, 2020 - link

    When they started, just about everyone that mattered was still running their own custom uarch. Apple, Nvidia, Qualcomm, etc. Of the big Cortex-A customers of that era: Mediatek wasn't a threat, Broadcom would never really enter the mobile market, and TI would withdraw from application processors altogether. From the picture of when Samsung started, custom cores were the way to go. Since then, Nvidia has constantly wavered on custom cores vs Cortex-A, Qualcomm has went to using optioned out Cortex-A cores, TI is still gone, Broadcom never even sniffed the market again, and Mediatek is still Mediatek. All the while, Apple's yearly CPU gains were slowing down and Cortex-A were getting a lot better.

    The picture just wasn't so clear back then.

    Samsung also had a chance to basically hire away one of AMD's "small core" teams (specifically the one which designed the Xbox One and PS4's CPU uarch), though that didn't pan out.
  • lmcd - Thursday, June 4, 2020 - link

    Nvidia wavering on custom vs not is irrelevant considering they entirely left the consumer portable device market. They couldn't get either in a low enough power profile at the performance they deemed acceptable.

    Qualcomm didn't choose to go to Cortex, they fucked up their aarch64 core design so badly that they scrapped it. Someone higher up realized that they could just coast on their modems, so they did.

    Broadcom didn't even matter back then so idk what you're referencing. They had 3-5 random design wins total and most were $0-on-contract type devices. Their lineup didn't have up-to-date graphics and they never used a higher-end CPU core.

    Quite frankly, Samsung should've gone a more extreme route than they did if they wanted a custom SoC: get an exclusive license to AMD's cat cores in mobile, and integrate them into a Samsung SoC. Tablets were still the rage back then, so you could pawn off the first few iterations on Android tablets. A Jaguar core, die-shrunk, would be solid as a smartphone CPU core even right now.
  • brucethemoose - Wednesday, June 3, 2020 - link

    Well theres a good lesson: deeper, longer term investments yield proportionally more competitive products.

    I get that Samsung "needed" a new uarch for every Galaxy, but in hindsight, they should've the bullet every other year.
  • brucethemoose - Wednesday, June 3, 2020 - link

    *bitten the bullet
  • lmcd - Thursday, June 4, 2020 - link

    It's worse than that, at least one year the revision of Mongoose core didn't align with the cores it was paired with. A few bugs arose due to inconsistent processing of instructions depending on which core a certain instruction ran on.
  • FunBunny2 - Wednesday, June 3, 2020 - link

    in due time, with any maths problem, there ends up being only one perfect solution. which is why all this hard ons with ever larger transistor budgets ends up, mostly, in various caches, not compute. has there been any fundamental change in ALU structure in decades?
  • eastcoast_pete - Wednesday, June 3, 2020 - link

    Question: how does the pipeline depth and prediction mistakes of the Mongoose cores compare with that of Apple's big cores? I'm asking as my impression of SARC's M designs was/is that they tried to repeat Apple's success in designing highly performant ARM design-based larger cores.
  • anonomouse - Wednesday, June 3, 2020 - link

    What's fascinating is how big M5's predictors and BTB's are when comparing to their direct competition. Cortex A77 cites a 8K entry BTB, 64-entry L1BTB, with undisclosed direction and indirect target predictor sizes, and yet M5 does worse on all of the branch heavy and large footprint workloads in SPEC (astar, bzip2, gcc, gobmk, sjeng) as well as all of the javascript benchmarks as well. I don't think Arm has said how any Kbits/Kbytes of storage are actually in their branch prediction structures, but at least in Neoverse N1 or Cortex-A76 the ICache SRAM blocks were clearly much larger in total area than all of the other SRAM in the front-end area of the core, which implies a total size not anywhere near 310KB like M5.
  • Santoval - Thursday, June 4, 2020 - link

    "The M6 would have been an 8-wide decode core, which as far as we know would have been the widest commercial microarchitecture that we know of – at least on the decode side of things."

    Nvidia's Carmel core (the core of their Xavier SoC) is 10-wide. However that's at the dispatch / retire stage and I'm not 100% certain if Carmel's decode width is also 10-wide (unless their dispatch block is not right after decode, which I doubt, it certainly should). Wikichip does not fully clarify but mentions that Carmel is "10-wide" and has a "wider dispatch (10, up from the 7 of Denver 2)" :
    https://en.wikichip.org/wiki/nvidia/microarchitect...
  • Santoval - Thursday, June 4, 2020 - link

    p.s. I am not sure if by the word "commercial" you have excluded SoCs for cars or not. If you mean retail / e-tail then someone who doesn't own or work for a car company probably cannot buy an Nvidia board with Xavier. It should be sold strictly B2B. Or not?
  • mode_13h - Friday, June 5, 2020 - link

    A Xavier NX kit can be yours for just $399:

    https://www.anandtech.com/show/15799/nvidia-announ...
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