TPS Rep...err PRS Documents

At ATI there’s a document called the Product Requirement Specification, PRS for short. It was originally a big text document written in Microsoft Word.

The purpose of the document is to collect all of the features that have to go into the GPU being designed, and try to prioritize them. There are priority 1 features, which are must-haves in the document. Very few of these get canned. Priority 2, priority 3 and priority 4 features follow. The higher the number, the less likely it’ll make it into the final GPU.

When Carrell Killebrew first joined ATI, his boss at the time (Dave Orton) tasked him with changing this document. Orton asked Carrell to put together a PRS that doesn’t let marketing come up with excuses for failure. This document would be a laundry list of everything marketing wants in ATI’s next graphics chip. At the same time, the document wouldn’t let engineering do whatever it wanted to do. It would be a mix of what marketing wants and what engineering can do. Orton wanted this document to be enough of a balance that everyone, whether from marketing or engineering, would feel bought into when it’s done.

Carrell joined in 2003, but how ATI developed the PRS didn’t change until 2005.

The Best Way to Lose a Fight - How R5xx Changed ATI

In the 770 story I talked about how ATI’s R520 delay caused a ripple effect impacting everything in the pipeline, up to and including R600. It was during that same period (2005) that ATI fundamentally changed its design philosophy. ATI became very market schedule driven.


ATI's R520 Architecture. It was delayed.

The market has big bulges and you had better deliver at those bulges. Having product ready for the Q4 holiday season, or lining up with major DirectX or Windows releases, these are important bulges in the market. OEM notebook design cycles are also very important to align your products with. You have to deliver at these bulges. ATI’s Eric Demers (now the CTO of AMD's graphics group) put it best: if you don’t show up to the fight, by default, you lose. ATI was going to stop not showing up to the fight.

ATI’s switch to being more schedule driven meant that feature lists had to be kept under control. Which meant that Carrell had to do an incredible job drafting that PRS.

What resulted was the 80% rule. The items that made it onto the PRS were features that engineering felt had at least an 80% chance of working on time. Everyone was involved in this process. Every single senior engineer, everyone. Marketing and product managers got their opportunities to request what they wanted, but nothing got committed to without some engineer somewhere believing that the feature could most likely make it without slipping schedule.

This changed a lot of things.

First, it massively increased the confidence level of the engineering team. There’s this whole human nature aspect to everything in life, it comes with being human. Lose confidence and execution sucks, but if you are working towards a realistic set of goals then morale and confidence are both high. The side effect is that a passionate engineer will also work to try and beat those goals. Sly little bastards.

The second change is that features are more easily discarded. Having 200 features on one of these PRS documents isn’t unusual. Getting it down to about 80 is what ATI started doing after R5xx.

In the past ATI would always try to accommodate new features and customer requests. But the R5xx changes meant that if a feature was going to push the schedule back, it wasn’t making it in. Recently Intel changed its design policy, stating that any feature that was going into the chip had to increase performance by 2% for every 1% increase in power consumption. ATI’s philosophy stated that any feature going into the chip couldn’t slip schedule. Prior to the R5xx generation ATI wasn’t really doing this well; serious delays within this family changed all of that. It really clamped down on feature creep, something that’s much worse in hardware than in software (bigger chips aren’t fun to debug or pay for).

Index The Other Train - Building a Huge RV870
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  • papapapapapapapababy - Sunday, February 14, 2010 - link

    Ok, ok, great read, but i have to hate a bit, 1,2,3 GO! hey Carrell here is my top priority feature for your next PRS

    1 -Drivers that dont suck ass-


    "The performance was still a problem and the RV740 was mostly lost as a product" ...

    the fuk? the 4770 is the BEST card i ever had, PERIOD. cheap, fast, cool, the perfect RV770, thanks !


    bla bla Carrell "He’s single handedly responsible for getting Eyefinity included in the Evergreen stack"

    Meh? who gives a sht. , Carrell give me console like gpu scaling, so we can finally play crysis at 1080p, another one for that PRS

    "Carrell went to David Glenn, head of software engineering at ATI and asked"

    drivers that dont suck, please?

    " There were also game compatibility concerns that made ATI not interested in the software approach"

    Lol i wonder why? i think i know why. Hardware, hardware, what about the software,Carrell?

    ok, thats it. not much to complain this time, flawless job ati guys

  • f0d - Sunday, February 14, 2010 - link

    long time reader/first time posting
    ive never felt the need to post anything but with this article i really wanted to say:
    "thank you"
    the insights we get in these articles is amazing (i also read the first when it was done)
    i like the "no technical or maketing bs" writing of this story and all the little pieces of information like with the eyefinity story and sideport
    please do as much of these type of stories as possible - it must be difficult to talk to the right people and get the right information out of them and also be allowed to publish it but it makes a great read
  • Robert Kooijman - Sunday, February 14, 2010 - link

    Awesome article Anand!

    Also specially created an account to inform you how impressed I am with articles like these. A real treat these behind the scenes stories in non-marketing language. Keep 'm coming, compliments!
  • - Friday, February 19, 2010 - link

    bravo

    when do the (tech industry) book's come out??
  • Kryten - Sunday, February 14, 2010 - link

    Informative, interesting, inspirational, edifying and very well written. Here's hoping for more research and articles like this.
  • greenguy - Sunday, February 14, 2010 - link

    Hi Anand, I've been reading your stuff for 3 years or so, I just created an account to tell you how awesome that article was. Very nice work. This sort of content is why I read Anandtech. (My other favorite articles have been the SSD articles and the i5-750 article.)

    I especially like to hear about AMD/ATI - I like having a serious competitor to Intel out there, and I commend AMD for opening up their graphics card documentation. I hope that they continue to fund the Linux driver development (both open and closed source). I also hope their CPU division can put the heat on Intel again, especially on the low power front.
  • at80eighty - Sunday, February 14, 2010 - link

    Anand I was just telling someone yesterday how I wish you guys got more popularity for the different approach you guys have

    between articles like this and the new beta Bench tab - I think I'm really looking forward to your proposed changes you promised this year
  • insurgent - Sunday, February 14, 2010 - link

    I had a really great time reading the article, thanks!
  • Markstar - Sunday, February 14, 2010 - link

    Also a big thank you from me for this wonderful article.

    It's exactly these kind of stories that I hope to find here every morning when I start the day.
  • JimmiG - Sunday, February 14, 2010 - link

    Well the late changes would explain why the RV870 isn't "perfect" like the 770 was. At every price point except at the high-end, it delivers more features, but less or similar performance as the previous generation. For example the 5770 is slower than the 4870, the 5750 is about the same speed and price as the 4850 and so on. Also at the high-end it's more expensive than the 4800-series ever were - the 4870 was only $299 at launch, the 5870 is still at least $399. By this month in 2009, the 4870 was down to $249!

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