
AMD's Jaguar Microarchitecture - luu
http://www.realworldtech.com/jaguar/
======
dmunoz
A bit meta, but for those who were not previously aware of Real World Tech, if
you enjoyed this article then do dig into the archives. David Kanter does
awesome writeups of (mostly) CPU and GPU architectures. I consider them a step
beyond Anand Shimpi's write ups, the most recent of which was recently shared
on HN, concerning Apple's Cyclone Microarchitecture [0]. They're published
very infrequently, with the front page of RWT still having two articles from
2012 appearing.

Although it's not exactly relevant to the type of programming I do, I still
find it useful to understand how modern processors actually work. At the very
least, reading architecture articles helps me to understand exactly why
certain processors are faster at specific tasks than others.

While I think it's great that David is being paid to write what he is good at,
it's slightly disappointing to me that his long form writeups are going to be
behind a pay wall at Microprocessor Report, which is covered in the recent
article "Splitting my time between MPR and RWT" [1]. The submitted article is
likely one of the few more in-depth articles he talked about being release in
the next several months.

[0] [http://anandtech.com/show/7910/apples-cyclone-
microarchitect...](http://anandtech.com/show/7910/apples-cyclone-
microarchitecture-detailed)

[1] [http://www.realworldtech.com/mpr/](http://www.realworldtech.com/mpr/)

~~~
AceJohnny2
How would you compare Kanter's writing with Jon Stokes' writeups on
ArsTechnica (back in the day)

(For example: [http://arstechnica.com/business/2010/09/intels-next-must-
hav...](http://arstechnica.com/business/2010/09/intels-next-must-have-upgrade-
a-look-at-sandy-bridge/))

~~~
dkanter
Jon and I are good friends, and we have very different styles. I don't write
for a mainstream audience - I write for computer architects, programmers, and
IT folks. My greatest strength (IMO) is that I can write clearly and in great
detail about complex topics such as CPUs, GPUs, etc.

Jon's strength is taking a very complex subject and making it much more
approachable to a larger audience. Sometimes that involves simplifying things,
but that's quite reasonable.

------
rkalla
The conclusion alluded to one of the most interesting parts of how Jaguar may
age -- summarized horribly -- we've never had a SOC shared between consoles
(XB1/PS4), desktops, laptops and tablets so closely that as the SOC shrinks
and the software on it is optimized further and further, you could imagine a
future in short-order (3-4 years?) where you might be able to buy a much-
shrunk Jaguar-based tablet that plays PS4 games at full fidelity.

His point is this has the potential of greatly extending the life of the
Jaguar SOC just by virtue of die shrinks and power savings and no significant
rejiggering of performance through the generations.

I thought that was a good call out... we never had this apples-to-almost-
apples comparison before to see this story play out.

~~~
cc439
The CPU side can definitely be matched but packing in the GPU power would take
a lifecycle at least as long as the last console generations.

Personally I'm dismayed by the level of CPU performance found in the new
consoles. Last generation quickly ran into a roadblock posed by the limited
memory capacity but I think developers have been hamstrung by a lack of CPU
horsepower right out of the gate. This is coming from a total layman who can
only interpret benchmarks but I know that Jaguar's IPC is very weak compared
to every other modern x86 design and the power of a single thread is a huge
limitation no matter how much you try to program around it.

~~~
tomlu
Ever since the PS3 games are very good at taking advantage of multiple cores
due to extensive use of data oriented design. Consequently in my experience
single-threaded performance isn't as important as you might think.

~~~
unsigner
PS3 games made everyone learn to take advantage of multiple cores, but the
incredible single-thread (more like thread and a half with careful manual
scheduling) performance of the SPUs should not be discounted.

~~~
lucian1900
The SPUs were fast, but still a simple design. Some workloads are entirely
inappropriate for them.

However, lots of generic CPUs will be perform well enough for any task, so
more of the overall workload can be expressed as asynchronous tasks.

Game devs aren't complaining about the CPU performance.

------
voidlogic
>>Fundamentally, AMD is the only company outside of Intel that is capable of
designing, validating, and shipping x86 microprocessors.

Everyone always forgets VIA and their CPU division, Centaur Technology. The
VIA Nano's are modern amd64 CPUs that perform well for their power envelope.
[http://en.wikipedia.org/wiki/VIA_Nano](http://en.wikipedia.org/wiki/VIA_Nano)

~~~
stephengillie
What happened to Transmeta and their Crusoe?

~~~
Osiris
I had a Crusoe based ultrabook during college (2002ish-2005). Performance
wasn't fantastic, but it was a third the size or less than most people's
laptops, and I could get 8-10 hours out of it. I didn't even take my power
cord to school with me.

------
fulafel
Fascinating that the GPU dragged x86 along to the consoles.

------
Aoyagi
As much as I wish for success of the only "real" competition Intel seems to
have, I'm still fairly annoyed that they (AMD) seem to have completely
abandoned their high-end CPU line (Vishera being the most recent specimen) and
any plans of making its successor.

------
techwatching
Is it weird that I wistfully read that as Atari's Jaguar Microarchitecture

~~~
rbanffy
I frequently wonder, alt.history-style, what would modern Atari and Commodore
computers look like.

Actually, that extends to other "classic" machines like Xerox Stars or Lisp
Machines. Or Liliths. It would be very interesting what products those ideas
would bring when combined with modern fab technology.

