Prioritizing ILP

Intel has held the single threaded performance crown for years now, but the why is really quite easy to understand: it has prioritized extracting instruction level parallelism with every generation. Couple that with the fact that every two years we see a "new" microprocessor architecture from Intel and there's a recipe for some good old evolutionary gains. The table below shows the increase in size of some major data structures inside Intel's architectures for every tock since Conroe:

Intel Core Architecture Buffer Sizes
  Conroe Nehalem Sandy Bridge Haswell
Out-of-order Window 96 128 168 192
In-flight Loads 32 48 64 72
In-flight Stores 20 32 36 42
Scheduler Entries 32 36 54 60
Integer Register File N/A N/A 160 168
FP Register File N/A N/A 144 168
Allocation Queue ? 28/thread 28/thread 56

Increasing the OoO window allows the execution units to extract more parallelism and thus improve single threaded performance. Each generation Intel is simply dedicating additional transistors to increasing these structures and thus better feeding the beast.

This isn't rocket science, but it is enabled by Intel's clockwork fab execution. Designers can count on another 30% die area to work with every 2 years, so every 2 years they increase the size of these structures without worrying about ballooning the die. The beauty of evolutionary improvements like this is that when viewed over the long term they look downright revolutionary. Comparing Haswell to Conroe, the OoO scheduling window has grown by a factor of 2x, despite generation to generation gains of only 14 - 33%.

The Haswell Front End Haswell's Wide Execution Engine
POST A COMMENT

248 Comments

View All Comments

  • kylewat - Tuesday, February 12, 2013 - link

    Compare the amount of space devoted to iOS v. Android. Your critique is not valid. The iPhone launch had a new version of the software, new hardware, new processor, the first apple designed processor, scuff gate, etc.

    S III may be a great phone, but it didn't have anywhere near the amount to talk about given it is an android phone (not even Nexus!).

    Anyway, Apple if anything is under served when compared to market share, they have a focused product line that doesn't follow trends like the Android Eco system as a whole (krait, jelly bean, etc do not need multiple reviews).

    Apple is the biggest company in the world driven by the biggest product in the world. The iPhone. That is just fact.
    Reply
  • Kepe - Friday, October 05, 2012 - link

    Also look at any other Apple product review. They are all ridiculously in-depth with analysis about almost every single component in the product. Macbook Pro with Retina Display got 18 pages, the 3rd gen iPad got 21 pages. Don't get me wrong, I like a proper review with everything analyzed, but it's only the Apple products that get these huge reviews. But compared to those massive Apple reviews, it's like all other products are just glanced over in a hurry. The new Razer Blade got 9 pages. Asus Transformer Pad Infinity got 8 pages. Reply
  • Peanutsrevenge - Friday, October 05, 2012 - link

    What the hell are you guys bitching about?

    Of course the iPhone articles are going to be longer and more numerous than GS3 articles.

    iPhone releases come with new iOS releases and have their own eco-system.

    Android phone releases use a common OS across them and therefore much of what's in one article doesn't need repeating in another.

    Anand liking Apple is not our problem, I can see why people like them (not so much Anand) and that's fine, personally I dislike them (hate was originally typed, but was edited due to being incorrect), but still respect them and respect people who purchase their products (and pay for their litigation).

    An entire page of comments talking about how Anand isn't allowed to like or talk about Apple products because you guys don't like is ridiculous, they're a PC company and should exist on a PC website.

    Grow up.
    Reply
  • Kepe - Friday, October 05, 2012 - link

    Sure, but I'm talking about dedicating entire, long articles to such things as the iPhone display or why it doesn't have a certain feature and so on. The SGS III has a very interesting display, too. Still it didn't get nearly as much attention. Of course Anand is allowed to talk about Apple products. What I want, though, is Anand(tech) to be as thorough in reviewing other products, too, or then stop making those huge articles only about Apple products. Because that is biased.
    In the Macbook Pro Retina article Anand talked about the cooling system and the fan blades for one page. When I read any other laptop review on Anandtech, cooling is briefly described in a sentence or two.
    Dedicating so much attention to just one company's products makes it look like Anandtech is biased. And that is not good.
    Reply
  • Magik_Breezy - Sunday, October 14, 2012 - link

    Hopefully because of these comments they'll finally see what we want, not some Apple crap. Good engineering stupid management Reply
  • Spunjji - Thursday, October 18, 2012 - link

    Nailed it. Reply
  • vFunct - Saturday, October 06, 2012 - link

    Android products would get more coverage if they bothered to do any engineering on them. Since they don't push the technology the way Apple does, they don't need a more in-depth review. Reply
  • StevoLincolnite - Saturday, October 06, 2012 - link

    You're kidding right? Hardware wise Apple has always been behind the curve compared to the competition in every facet of it's product line-ups or very quickly beaten. Reply
  • lmcd - Saturday, October 06, 2012 - link

    Umm, I would disagree there. Apple has always been ahead of the curve in GPUs and this is the FIRST TIME SINCE BEFORE THE A-SERIES that Apple has had a GPU without an overwhelming lead on the competition for more than half a year.*

    While GPU selection isn't always huge, it's one of the biggest points of differentiation in mobile chips, along with power use.

    *excluding the A4 if you count from when it was first in a phone as opposed to in a tablet.
    Reply
  • Magik_Breezy - Sunday, October 14, 2012 - link

    The last time I played a game on my phone was about 8 months ago and I'm 15! To say that Apple pushes their hardware is naive as it gets.
    The Galaxy S III was the best purchase Ive made, even my mum doesn't like my iPhone 4.
    Reply

Log in

Don't have an account? Sign up now