Apple's Swift: Visualized

Section by Anand Shimpi

Based on my findings on the previous pages, as well as some additional off-the-record data, this is what I believe Swift looks like at a high level:


Note that most of those blocks are just place holders as I don't know how they've changed from Cortex A9 to Swift, but the general design of the machine is likely what you see above. Swift moves from a 2-wide to a 3-wide machine at the front end. It remains a relatively small out-of-order core, but increases the number of execution ports from 3 in Cortex A9 to 5. Note the dedicated load/store port, which would help explain the tremendous gains in high bandwidth FP performance.

I asked Qualcomm for some additional details on Krait unfortunately they are being quite tight lipped about their architecture. Krait is somewhat similar to Swift in that it has a 3-wide front end, however it only has 4 ports to its 7 execution units. Qualcomm wouldn't give me specifics on what those 7 units were or how they were shared by those 4 ports. It's a shame that Intel will tell me just how big Haswell's integer and FP register files are 9 months before launch, but its competitors in the mobile SoC space are worried about sharing high level details of architectures that have been shipping for half a year.

Apple's Swift core is a wider machine than the Cortex A9, and seemingly on-par with Qualcomm's Krait. How does ARM's Cortex A15 compare? While the front end remans 3-wide, ARM claims a doubling of fetch bandwidth compared to Cortex A9. The A15 is also able to execute more types of instructions out of order, although admittedly we don't know Swift's capabilities in this regard. There's also a loop cache at the front end, something that both AMD and Intel have in their modern architectures (again, it's unclear whether or not Swift features something similar). ARM moves to three dedicated issue pools feeding 8 independent pipelines on the execution side. There are dedicated load and store pipelines, two integer ALU pipes, two FP/NEON pipes, one pipe for branches and one for all multiplies/divides. The Cortex A15 is simply a beast, and it should be more power hungry as a result. It remains to be seen how the first Cortex A15 based smartphone SoCs will compare to Swift/Krait in terms of power. ARM's big.LITTLE configuration was clearly designed to help mitigate the issues that the Cortex A15 architecture could pose from a power consumption standpoint. I suspect we haven't seen the end of NVIDIA's companion core either.

At a high level, it would appear that ARM's Cortex A15 is still a bigger machine than Swift. Swift instead feels like Apple's answer to Krait. The release cadence Apple is on right now almost guarantees that it will be a CPU generation behind in the first half of next year if everyone moves to Cortex A15 based designs.

Custom Code to Understand a Custom Core Apple's Swift: Pipeline Depth & Memory Latency
Comments Locked

276 Comments

View All Comments

  • rarson - Thursday, October 18, 2012 - link

    Me too, other than the stupid proprietary connection that jacks the price of everything up.
  • Spunjji - Friday, October 19, 2012 - link

    I sit pretty firmly in this camp, too. Despite the physical durability flaws, I do find the overall package of the iPhone 4/4S/5 to be superior to most comparable 'Droid handset. I just find the software to be unbearably obstructive to my desired use patterns.
  • steven75 - Wednesday, October 17, 2012 - link

    Maybe some people want a still larger display but keep the industry leading app support, industry leading hardware ecosystem, airplay, apple store support, industry leading resale value, industry leading OS upgrade support, and without any carrier bloatware?

    Seems pretty possible to me.
  • GotThumbs - Tuesday, October 16, 2012 - link

    "we've just got to deal with it." Wrong. You have to "deal with it".

    Believe it or not....everyone does NOT own one of these phones. The idea of getting a brand new item, be it a car, camera, laptop, tablet or phone and having to deal with the fact that that the companies quality controls are sub-standard is one of the lamest things I've heard....Oh! besides the number one example...... "You're holding if wrong" - Steve Jobs.

    I try to not let this kind of monologue that reeks of Apple fanism not bother me...but come on! Talk about romancing about a freaking phone. Please keep it to a level of unemotional comparisons and the feel free to give your personal thoughts and not assume to speak for everyone else.

    The fact that you felt compelled to write 5 or more paragraphs on the anodizing process is just pathetic. I stopped reading about it after the first paragraph and skipped to the bottom. I thought this is supposed to be a phone review, not a discovery channel episode on the anodizing process. I can't speak for you or anyone else, but I'm pretty comfortable telling you most consumers probably don't care about the process of anodizing, they just expect a quality product for their money.

    People are paying good money...in a bad economy and your saying all they can do is "deal with it"? How about having an open mind and mention they have the choice to buy a different phone or wait for Apple to fix it in their next generation. Your only position appears to be....suck it up, its Apple and thats just part of being in the collective.

    Again,,,,, YOU do not speak for everyone so please drop the "WE".

    Rant done.

    Best wishes to all on your choices in life.
  • crankerchick - Tuesday, October 16, 2012 - link

    Talk about overreaction. Keep the statement within the context of the article. iPhone users have to deal with it if they want to remain iPhone users. Anand is an iPhone user as well are more than a few people reading his review--thus the use of the word "we" instead of the use of the term "iPhone users."

    That said, he should take care lose the "we" but wow, what a rant for something that one can easily use common sense and say, "No I'm not stuck with it." Other bloggers and review sites do the same thing.

    LOL, everyone is always looking for someone to point the fanboy finger at.
  • KPOM - Tuesday, October 16, 2012 - link

    Apparently you have never read an AnandTech review. They go into that kind of detail all the time. That's what people like about them. You aren't going to read that in a CNet, The Verge, or Engadget article. You might get some of that at Ars Technica. But AnandTech goes into excruciating detail.
  • VivekGowri - Tuesday, October 16, 2012 - link

    I mean, it's not like Apple is going to radically alter it a month after production starts, so if you want an iPhone 5, your options are to either put a case on it, or suck it up and live with the scratches. Alternatively, you could buy a 4S (if you want iOS) or any other phone that floats your boat.

    I'm a guy that daily drives a Galaxy Nexus, so accusing me of iOS fanboyism isn't necessarily the most productive way of going about your day.
  • phillyry - Sunday, October 21, 2012 - link

    Yes!

    Well said Vivek.

    But ya, Apple should still have the pressure put on them. So, I could see how people might take it the wrong way. 'Cause it could seem like you're just like, "It's all good Apple, we'll just suck it up." When, in actuality, your ideas are as you stated here. As per the OP's rant, I definitely thought it was off-base but could see where he would draw that conclusion, as it came across that way to me too. And, perhaps like me, he has a hard time keeping track of who uses which phone from the podcasts.

    Again, well retorted though.
  • jiffylube1024 - Tuesday, October 16, 2012 - link

    You are seriously complaining about the depth the review went into on the anodizing
    process? You're reading a review of a product and you're complaining that you're being given more information? How about you just skip over that section if it doesn't interest you.

    I lol'ed that you called that kind of serious scientific investigation into the anodizing process (which I found incredibly informative) "pathetic". Real, fact-based journalism apparently bores you; you'd just rather read opinion pieces and pass judgment on them. How high minded of you!

    Other reviews don't even mention anything about the anodizing process other than that it's there. I don't get why you'd even bother reading a review on AnandTECH if you don't care about the technology...

    As for the author's position to "deal with it" (the anodization scratch issue) -- what more can the author do? He can't fix the problem or even address it from a manufacturing standpoint. The review points out the issues with it; the decision making process is up to the consumer and the fixing of the problem is up to the manufacturer.
  • GotThumbs - Wednesday, October 17, 2012 - link

    "Other reviews don't even mention anything about the anodizing process other than that it's there. I don't get why you'd even bother reading a review on AnandTECH if you don't care about the technology..."

    Anodizing a piece of aluminum does not constitute "technology" when compared to the design of a SoC or camera, at least in my opinion. I see it as a finishing process. My point is that a side link to more detailed information on the anodizing process would have sufficed and kept the reader on track with the hardware review.

    I visit Anandtech on a daily basis and have been reading/visiting this site from the early years when Anand was still in High School. I thoroughly enjoy reading/learning about how new technologies in hardware are evolving and when they are compared to other current hardware available in the marketplace. But I feel there has been a growing tendency in Apple product reviews to have a hint of personal/emotional input rather than sticking to an analytical/technical assessment and let each reader digest the information without the personal emotional spin. It's like todays "News" casters interjecting thier personal thoughts/opinions on a news story. I prefer to get the facts and come to my own conclusion.

    In case you haven't realized, more and more in todays society, we are "Marketed to" in ways that are growing exponentially. Todays marketing companies continue to market to us using methods not just like Product Placement in TV shows, Reality shows, Movies, Red Carpet runways. etc., but on FB, Twitter, blogs, and weak "tech reviews" like CNN's (Read more like product ads than a review) etc. Because of this bombardment of marketing from every possible source imaginable and newly evolving, I don't think its wrong to call out a reviewer when I feel there is even a whiff of non-neutrality. They can take it with a grain of salt or ponder on their next review to be sure they are approaching it in a clear and unbiased manner.

    Complacency in a society and lowering on one's expectations is not something to embrace, its to be challenged and called out.

    Listen, no one is perfect and yes I may have been a little high strung in my post, but it was fueled by emotion and passion and I won't apologize for that.

    I do apologize to Vivek Gowri if I offended him in any way. It was not my intent.

    Best wishes

Log in

Don't have an account? Sign up now