Double-Whammy Look At The Pentium 4

SystemLogicNet writes: "We at SystemLogic.net have just taken a technical look at the Pentium 4 architecture. In the article we go over all the basics that all the other sites cover like the double pumped ALUs, iSSE2, the longer pipeline, etc, but in addition we have some discussion about how different program structurings have an impact upon the design, and performance of the Pentium 4. One of the major areas where this comes into play is how complex data structures interact with the underlying philosophy that the Pentium 4 is built upon -- extreme bandwidth. This Pentium 4 technical background can be read over here. At the same time, we've done a rigorous analysis, including benchmark description and discussion regarding the Pentium 4's performance, and this can be read over this way."

Comments

Re:Sad state of affairs

[Diomedes01]

Most of you probably think 90% is good, but think of it this way: 1 out of every 10 times you try and click on something, or double click something, or open a file, whatever, it fails. Every 10th Word file fails.

Yet again, another Slashbot posts on a topic about which he appears to have no knowledge whatsoever. This analogy is by far one of the worst I have ever seen. Do you even know what branch prediction is? Yes, 90% may not be great, but it's certainly not the huge problem that you make it out to be. There are many other architectural factors that come into play here.

Personally, I don't agree with the Brute Force methodology by Intel; I prefer simpler, cleaner and more elegant solutions. It is difficult to deny, however, that the brute force method has worked so far. Yes, yes, I know that the "x86 suxx0rs" crowd is now going to come out of the woodwork. Let me just say this: It may not be the best architecture, and it may be kludged for backwards compatability, but... it works, and it's cheap. With any luck, the 64-bit processors will be able to buck the trend of backwards compatability (has anyone heard anything about this with regards to Itanium and/or AMD's 64-bit chip?).

Re:Sad state of affairs

[IAT]

"Wrong branch taken: the correct instruction is fed into the pipeline a tiny fraction of a second later and you're set."

*Bzzzzt!* Wrong. Accurate branch prediction is expecially important when you're dealing with the P4's whopping 20 stage pipeline. Each incorrect prediction costs quite a few clock cycles and slows down overall processing signifigantly. See this ArsTechnica article for details.

Upcoming AMD technology.

[Dwain_Snyders]

If he was writting in C and using asm for the most preformance intensive functions as is now standard practice for the non lazy (who know their target platform and optimize for it)it would not be such a chore. Perhaps if he used an Intel compiler plugin that optimizes for the P4 he would not be complaining. Should he have to do so? Nope, but it seems to be the way everything is heading whether you look at AMD or Intel.

While I agree that as technology moves forward the traditional ways of X86 programming will have to expand along with the technology, and in some areas change completely, I'd just like to share something about upcoming AMD technology in this regard.

The next-generation chips from AMD are being designed with programming optimizations done at the firmware level. For example, a FORTH interpreter is being ingrained into the preprocessing area on the chip die itself. This makes it easier not only to add firmware-level software like BIOS, bootloaders, etc more easily, without resorting to running the code through a compiler into X86 instructions and machine code, but it will also make it much easier to write more optimized C compilers (and other compilers for that matter). If you combine this with the improved instruction technology that AMD will be incorporating, it makes for a very powerful new platform for all programmers.

Dwain Snyders
Research and Development, AMD

amd 1.4 ghz is available and kicks butt

[lupine]

The 1.4 ghz athlon has been out for a couple months now... the 1.1 ghz athlon has been out for at least 10 months.

Here is a june 6 pcworld review where an amd 1.4-GHz system is "the fastest system yet tested by PCWorld.com" beating out 5 systems based on the 1.7 ghz p4.

Here is a tech report review of an amd 1.33 vs intel 1.7 where they conclude: "Intel's new entry, the 1.7GHz Pentium 4, performs about like a 1.2GHz Athlon in most situations."

You cant get duel processing power from a pentium 4 like you can with an athlon.

optimized for Xtreme Programming? please.

[krog]

it's sad that Intel feels the need to optimize for an untested and foreign program structure (XP) when they haven't even gotten imperative programming optimizations done right. oh, and that failing-branch-10%-of-the-time might knock the wind out of the P4's sails (sales) too. i'll stick to the Open Source support of the Athlon.

Intel is struggling

[ioman1]

Intel's biggest problem is that they are losing inovative engineers. Anyone with any real talent has left Intel already. Management is running the scene and they need to pull their heads out of the ground to see what is going on. A good example of this would be with the Rambus fiasco. It was the managers that made the decision to use Rambus, not the engineers. Another example would be the web tablet. This product has been in development for a long time. In fact, if people at the last CES didn't show much excitement for it, the Web Tablet would have been scratched already. By the way, 80% of the webtablet group have been either laid-off or re-deployed to other groups. What does that tell you?

Re:Misleading graphs

[SystemLogicNet]

The graphs were a mistake that was made in Excel...I have fixed them and uploaded them where they start at 0 (I'm the writer of the review). You can see an explanation here:

http://www.systemlogic.net/boards/showthread.php?t hreadid=1404