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HyperTransport 3.0 Ratified
Hack Jandy writes "The HyperTransport consortium just released the 3.0 specification of HyperTransport. The new specification allows for external HyperTransport interconnects, basically meaning you might plug your next generation Opteron into the equivalent of a USB port at the back of your computer. Among other things, the new specification also includes hot swap, on-the-fly reconfigurable HT links and also a hefty increase in bandwidth."
I can see an interesting situation where you could have a traditional CPU, to which you could plug in additional external processor modules as your needs expand. (assuming the OS could handle sharing out multithreaded apps over a variety of different multi-CPU configurations.)
Dave has a processor intensive project this week? He gets the big stack plugged into his machine until someone else in the office needs it.
Server getting bogged down? Add another couple modules to the system.
I like the idea.
m-
You catch enchiladas by picking them up behind the head and holding them underwater until they don't kick anymore -VeGas
I really can't see it being that kind of socket!
Oh I dunno, take it out to dinner, buy it a few drinks, you never know what could happen.
Not to be pedantic, but while I might not want to dedicate a large chunk of ram to a specific processor in such a manor, I might want to live in that manor, and maybe have my serfs carry out the computations for me.
HT 3.0 increases the bandwidth to 41.6 GB/s, that's 86% more than 2.0. It's also expected to be backwards compatible with current motherboards using 2.0. The new processor will run with 3.0 speeds while the motherboard will be stuck with 2.0. The new Rev. F AMD cpus are expected to have HT 3.0. It should help with multi-processor systems where the high bandwidth connects each cpu.
Whoever subimtted the article doesn't understand what the external HT links are for. They are _NOT_ a replacement for USB or any other similar technology. External HT is used to link multiple chassis together to form a large SMP box. This is similar to infiniband, etc. This is NOT designed to be a way to just plug in a CPU to an external port. Read the pdf:
p df
http://www.hypertransport.org/docs/tech/ht30pres.
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"Hum... I can't quite afford a whole new system or even a motherboard and two new procs... I'll just add a new one to the back of an existing one" ...Except you'd need a hypertransport 3.0 motherboard to begin with, and enough appropriately clocked RAM to make use of the processor. The whole "External CPU" idea was just speculation anyway; it's not mentioned anywhere in the article.
Point being, you'll never be able to plug a new opteron into _anything_ that's sitting in your closet right now.
Most of the HyperTransport updates look to be good (and, frankly, about time) but I am highly concerned that if certain manufacturers (such as Broadcom) haven't even bothered to do better than a fragmentary 1.x and have ignored 2.x entirely, there is little hope that they'll do much with 3.x.
And that's the big problem. If AMD are the only ones who ever implement the specification in full, correctly, then it doesn't offer any significant advantage. It isn't universal enough to be useful. That is the killer that has murdered so many excellent technologies. Being good - even being the best - isn't enough. If a rival is more widely adopted, then it'll be the rival that wins. The marketplace doesn't reward quality, it rewards popularity. Quality achieves nothing.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Why are MacBook Pros so much faster than Powerbooks?
:/
The MacBook Pro sports a 666Mhz DDR FSB, while the Powerbook sports a 133Mhz FSB. It doesn't matter how fast your processor is if you don't have a fast enough way to power it (much like a V-12 will not do well with a single-barrel carb used on a lawnmower engine).
The Von Neumann bottleneck is the significant limiting factor in all machines, once your working set of data exceeds that of your L1/L2 cache. Suddenly your 1.5 Ghz G4 is 266 Mhz
Faster hypertransport means happier users of AMD machines. My AMD64 beats the pants off my Sempron 2500 because its 800Mhz HT bus allows it to do context switches in less than 1/3rd the time of the Sempron!
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Yup... It has always been thus. The difference is that the high-end processors do exotic things and then Intel/AMD suck it in when it is ready for commoditization. The x86 has *always* been behind in those types of technologies (but usually pretty far ahead in tricks to make the x86 ISA fast) because those technologies are high-end. Eventually, it all trickles down to commoditization and then we get it in x86s.
The reason fiber optic (particularly glass core) is so expensive is due to the difficult and sensitive process required to manufacture that cable, though the materials used are extremely inexpensive. The diameter of the glass core must be matched exactly to the wavelength of light to travel over that fiber. In addition the composition and purity of the glass must meet certain standards to prevent reflection, signal attenuation, or signal skew, all of which would result in inconsistent or degraded performance. As far as the lasers being cheap, yes a laser can be cheap, but again the same demanding requirements apply to both versions of laser used in data communications, which again increases the manufacturing cost.
So fifteen years ago everyone else had 20GB/sec buses? Funny, Sun seems to think they were using MBus, which peaked at around 350-400MB/sec. And HP was dropping CPUs on a GSC bus running at ~ 250MB/sec. I'd look up what state of the art was for SGI and IBM, but it would be silly. AMD and Intel surpassed other chip vendors on a number of fronts years ago.
"Are you suggesting AMD buy SGI?"
Hell, I've got some change left over from lunch, I'm thinking of buying SGI.
I rarely criticize things I don't care about.