Samsung’s foray into the eight core processor market hasn’t been without its problems. The company’s original Exynos 5 Octa, the Exynos 5410, which is found in the Samsung Galaxy S4 seemed to promise much with its big.LITTLE design that allows the processor to use four low-energy Cortex-A7 cores together with four more powerful Cortex-A15 cores. However it turned out that due to some design flaws in the 5410 the processor only allowed four cores to be running simultaneously.
When Samsung released details of the next generation of the Exynos Octa, the Exynos 5420, it was assumed that Samsung had fixed the issues with the original 5410, however its wording remained vague, “The system switches amongst eight cores of Cortex-A15 and Cortex-A7 processors depending on workload, selecting the right core for the right task and saving power in the process.” The good news is that Samsung has now confirmed, via a musical video posted on YouTube, that the Exynos 5420 can use all eight cores simultaneously.
ARM’s big.LITTLE architecture allows for multi-core processors to run in one of two modes: a migration mode and a Heterogeneous Multi Processing (HMP) mode. In the first mode, which is used in the Exynos 5410 and the Samsung Galaxy S4, the low-energy A7 cores are used by default and then when things get busy the A15 cores are activated while the A7 cores are shut down. This means that the Exynos Octa 5410 only uses a maximum of four cores at once, making it the same as a quad-core processor but with some clever power saving technology. I originally suggested that the lack of HMP support for the 5410 was due to a software deficiency and that by adding a HMP scheduler to the Linux kernel would allow the 5410 to run in HMP mode. However it turns out that that 5410 is limited to migration mode because of a hardware deficiency, specifically in the cache subsystem that provides a coherent cache across all the cores and allows for seamless switching between them.
The Exynos 5420 fixes these problems and the cache subsystem, know as the Cache Coherent Interconnect (CCI), is fully working – allowing the processor to be used in a HMP mode. Heterogeneous Multi Processing is a clever piece of technology because the Linux kernel (in Android) needs to know that not all the cores are equal. In an SMP system all the cores are the same and so the scheduler can just distribute tasks to any core depending on workload. But with HMP the scheduler shouldn’t try and run the latest 3D game on one of the A7 cores it should be moved to the A15 cores. As Samsung puts it, “If you’re an avid mobile gamer who’s into FPS games with complex graphics or fast-paced, high-frame-rate racing games, the ‘big’ Cortex-A15 cores are there to do the heavy lifting.”
Over the next few weeks the Galaxy Note 3 will start to ship and I am sure that keen Android developers will be picking apart the internals of the device and looking at the functionality of the Exynos 5420. Samsung have a good track record for releasing the GPL licensed software components of their Android phones so once this code is published it will be relatively easy to look at the HMP scheduler included in the version of Android used on the Note 3.
What does this mean? It means that the Samsung Galaxy Note 3 will be the first true eight core device available to the general public, albeit a heterogeneous octa core system.
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Would rather the snapdragon 800 and cyanogen mod than this gimmik crap
why not this if they manage some real benefits such a extending battery ? I for one am not comfortable with qualcomm replacing intel (like how intel dominates on the desktop). I’d love to see nvidia/ tegra, mediatek, samsung/ exynos, etc. unfortunately ST ericsson, broadcom & TI-OMAP have either shut shop or fallen by the wayside
not a “bright” spark
Don’t think note 3 will get it. Too many people week hold out for it which will massively affect early note 3 sales (I know I will If I’m wrong). It’s only 9 months till the next galaxy S release. The S5 and note 4 are more likely to receive that upgrade.
well the soc is just one part of performance you see from a smartphone. I for one am curious if sammy improved the screen tech on the note 3 from the s4. The screen in itself if the biggest battery drainer.
The note three has it is what this article is saying, at least some versions of it(3g only). The 5420 is the chip in the note 3 (3g, wifi version) and the wifi, and wifi 3g versions of the note 10.1-2014. I heard somewhere that there is going to be a Q4 Implementation so if i doesn’t ship with the explicit capability, it will at least be the correct architecture to support HMP; therefore could be implemented via update in the near future I would think.
so what???? I bet samsung will just say something like there was production issue due to time or that all the parts of the world that actually matters will not get the chip becuase its not LTE ready… whatever
yeah…told you people so. technology takes time to develop, mature and progress to the point where it does what it originally was supposed to. can’t wait to get my hands on my Note 3 Octa variant.
right now I would rather have the tried and true s800. Would you really want something that had to be fixed from something that was almost broken but was sold anyway?
I wouldn’t have minded if it was just the S800 in the Note 3. I am getting it for it’s features, screen size, stylus etc after all, not because of what CPU/GPU is inside (although it has to bring the performance too). But I like innovative ideas. Yes the first Octa is / was a little bit dodgy, but its still does the job well enough. The new one will take it to the next level, while being a bit different. and that’s kinda what I like, something different.
I think that people tend to nitpick a bit too much coz things don;t deliver exactly what it says on the press release/ spec documentation.
Promising an octa-core processor and releasing what amounts to 2 quad-core processors glued together is considered “nitpicking”?
Glued together…OMG…seriously…Gimme a hammer…
it is nitpicking to whine over the fact that it’s not a true Octa… it has 8 cores, does it not…?
it just does not use all of them at once… and that was explained in the countless press releases (ARM’s one on Big.Little Architecture included) and articles across the web.
it still has 8 cores, albeit in 2 x quad core format.
bottom line. I like it. I want it. People moan to much…
Sammy, please price it right and ship one to me now.
abazigal. Yes, you are nitpicking. Samsung didn’t try to hide the fact that the processor worked the way it did – nor did anyone involved with it. It delivered what was promised. Now, it has been improved.
If it had been Apple on the other hand – as was the case with their “input coordinates and we will send you to the middle of the desert so you can die of thirst” mapping app that they spitefully put on their site and forced all their users to use for awhile – you would have heard loads of hype about their “revolutionary” processor and nary a word about how it wasn’t greater than great – until they were forced to actually admit they screwed up (as was the case with their mapping app.)
Samsung is a big company, staffed by humans. Humans and companies don’t always get things right and perfect the first time through – perhaps you do and therefore are above reproach in any and all things to which you apply what would obviously be your none too small abilities – but the rest of us, alas, daily face the fact that we may not have gotten it exactly perfect yesterday, but will do our best to make it better today.
Samsung makes the best components by far. If I where to launch a satellite it would be powered by note 3 guts. However, I would never have them build the sattelite inclosure. Nor would I buy a smartphone from them after my note 2 for the same reason.
Its supposed to do whatever it is marketed to do.
So India will get true eight core exynos 5420 processor
i really like it
S800 or Exynos? Why not BOTH? =p
Give us battery that last a week and minimum 128GB internal storage then we can talk about 8 cores or 4k (to all manufacturer not just samsung)
well u can choose the 64gb and put a 64 gb SD so 128gb is possible in note 3
I said internal memory and minimum because if lowest is 16g/32b then bigger ver will be overpriced. $100 more for bigger storage is ridiculous.
Why dont manufacturers just put a Intel Core I7 Extreme Edition Haswell family inside and clock it at 3.0 Ghz and hexa core
Well written article Gary. Clear in terms of background leading up to present; the ins and outs of the “controversy” (tempest in a tea pot) surrounding the processor, what has been changed for the better, what has remained the same and what all of this bodes for those of us lucky enough to enjoy the prowess and power of the processor! Who could ask for anything more?
Also, you made it easy to understand the technology.
Thank you, very kind of you to say so.
Exynos 5410 octave WONT have HMP ,all this is BS ,you people are dumb enough yo just copy the whole without reading the source of the news ….:face palm:
Ignore this ,wrong place