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标题: Jim Kahle：We have a 65 nanometer part [打印本页]

作者: Edison 时间: 2006-10-27 17:13
标题: Jim Kahle：We have a 65 nanometer part

Jim Kahle is the chief architect of the Cell microprocessor and the visionary behind the multiprocessing beast that is the heart of the PlayStation 3. He led IBM's side of the chip alliance with Sony and Toshiba. He has been designing microprocessors since the 1980s and was one of the founding members of the Somerset Design Center, the chip design house formed by Apple, Motorola and IBM at the onset of the Power PC alliance. He was also the chief architect of IBM's Power 4 microprocessor which was used in IBM servers and Apple's G5 Macintosh machines. I caught up with him after his recent keynote at a Cadence Design Systems conference.

DT: It seems like you finished the Cell chip designs early. The first prototypes came out in 2004 and this is 2006. Did you still need a lot of development time after that first tape out?

JK: We used that first tape out to get the initial software up and running. There were modifications we did to the chip over time. The design center is still active and participating. Our roadmap shows we are continuing down the cost reduction path. We have a 65 nanometer part. We are continuing the cost reductions. We have another vector where we are going after more performance. We have talked about enhanced double-precision chips. Architecturally we have double precision but we will fully exploit that capability from a performance point of view. That will be useful in high-performance computing and open another set of markets.

DT: That sounds like it’s not a PlayStation 3 chip?

JK: Yeah, it is a different vector. For us to extrapolate. We will push the number of special processing units. By 2010, we will shoot for a teraflop on a chip. I think it establishes there is a roadmap. We want to invest in it. For those that want to invest in the software, it shows that there is life in this architecture as we continue to move forward.

DT: Right now you’re at 200 gigaflops?

JK: We’re in the low 200s now.

DT: So that is five times faster by 2010?

JK: Four or five times faster. Yes, you basically need about 32 special processing units.

DT: AMD bought ATI Technologies and they signaled that a combined CPU and graphics processor is not so far off. They are going to do an initial crack at it for emerging markets in 2007. Is that something you see coming and is Cell anticipating this world already?

JK: If you look at a gaming system, there is obviously a close relationship between graphics and the main processing elements. Over time we will look to see how effectively we can make the main processor and graphics tie together. I won’t go beyond that.

DT: With Cell and PlayStation 3, was there a lot of thought about whether you needed a graphics chip?

JK: We explored that to understand the bounds of what we could do with the architecture. If you look at some of our ray tracing, ray casting techniques, they are very effective. People have worked on some software caches to help out the ray tracing. I wouldn’t say that is graphics processing because ray tracing is a little different. We’ve explored the bounds on this to understand where it can contribute with pure graphics processing. Over time, we have been exploring that.

DT: With Moore’s Law, is it inevitable that they will wind up on one chip?
JK: If you look at the PlayStation 2, eventually the graphics did get integrated into the Emotion Engine. Sony has talked about that. Definitely from a cost reduction view. Now we have to look at it from a performance point of view too. That is something we have to study for the future. Even beyond PlayStation 3. I don’t know if it is inevitable. We have to understand the pros and cons of it

http://blogs.mercurynews.com/aei/2006/10/the_playstation.html

作者: Eji 时间: 2006-10-28 02:32
所以結論是65nm版的Cell，SPE會有全速倍精度能力。:loveliness:

作者: RacingPHT 时间: 2006-10-28 12:58
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作者: Edison 时间: 2006-11-30 18:17
http://we.pcinlife.com/thread-663389-1-1.html

看ISSCC 2007了。

作者: Eji 时间: 2006-12-2 01:32

原帖由 RacingPHT 于 2006-10-28 12:58 发表
其实和G7x搭配, 我觉得Cell没有FP16的支持蛮可惜的。因为short int我觉得价值不大, FP16做成之后可以直接喂给G7x. 吞吐量大一倍, 然后这个精度也还可以.

現在的問題是Cell 塞給RSX ，RSX一定能吃？
或者說，要它能吃要多少代價....

照理來說Cell 還是可以跑FP16啦，只是相對於FP32不會變快而已。

作者: RacingPHT 时间: 2006-12-2 13:51
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作者: Edison 时间: 2006-12-2 14:13
如果是把CELL用做VS/GS类的操作，这不是什么问题吧，毕竟Vertex Shader都得fp32的。

作者: Eji 时间: 2006-12-10 21:13
話說為了配合Cell，現在看來RSX做了很多修改，變得不太像本來的G7x.....
還包含了PS2 GS的相容模式。
目前PS3都以G7x相容性的code在執行，還沒有人使用到RSX自己的模式；
雖說RSX本身的shader performance應該還是與同規模的G7x無異，但是應該可以期待一些與Cell的連動，而這應該是即使有同等級CPU的PC也無法處理的東西。

要達到同樣的能力，大概只有單一個大晶片才能處理得好，比方說現在的G8x。
反過來說，Cell+RSX在成本上的觀點就變得有競爭力了。

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