SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Technology Stocks : Intel Corporation (INTC) -- Ignore unavailable to you. Want to Upgrade?


To: Charles Gryba who wrote (151168)12/5/2001 12:59:34 PM
From: wanna_bmw  Read Replies (1) | Respond to of 186894
 
Constantine, Re: "Why would the P4 team omit something as lightweight as a simple decoder?"

If it were so simple, they wouldn't have omitted it. My guess is that an extra decoder might have:

a) limited clock frequencies
b) taken up too much die size
c) complicated certain logic

While weighing in all these things, they might have done performance estimates, and found it to be 1% or 2%, which might not have made it worth it. Keep in mind that in the far majority of the code, the trace cache is said to have a hit rate of a 8-16KB iL1 cache, which is around 85%. Optimizations can make that hit rate even larger.

But this is just a WAG. The truth, though, is that there is a lot involved in designing a new architecture - and nothing is done "just for the hell of it". There is always an educated reason behind it. That's why I consider this exercise so futile.

If, for some unknown reason, the architects *did* put a half speed decoder inside, they would have had a good reason. They wouldn't be blind to any bottleneck obvious to a bunch of forum posters like ourselves. All Kapkan and Jozef are doing is trying to prove that they are smarter than an experienced team of CPU designers. It's idiotic.

wbmw



To: Charles Gryba who wrote (151168)12/5/2001 2:10:37 PM
From: Timothy Liu  Respond to of 186894
 
Why would the P4 team omit something as lightweight as a simple decoder?

Because the trace cache is already providing a better performance boost. There is no point spent more real estate on things that is not a bottleneck.

Just my 0.02$
Tim