The great wheel of semiconductor life continues to turn. 'Tis the season to start gearing up for the International Solid State Circuits Conference in San Francisco. The ISSCC event is the second event of each new year, following the Consumer Electronics Show, where new PC processors and sundry other computing gadgets are brought …
Cache is king!
"According to the ISSCC abstract, Intel will be showing off a "12-wide issue" Itanium chip with eight multi-threaded cores that has a ring-based system interface and a combined cache on the die of 50 GB. That's a weird number, with the Itanium 9300 having 512 KB of L2 instruction cache, 256 GB of L2 data cache, and 6 MB of L3 cache per core. Just keeping all of those cache sizes the same and ramping up to eight cores puts you at 54 GB."
How much cache?? MB I think, not GB...
Paris cos I'm sure she's given a few bites..
The numbers given don't even add up anyway. 256GB L2 per core cannot equal 50GB total.
Should be 256 Kb L2 per core and, as you said, 50MB total.
Well, IBM's new Mainframe cpu z196 which they call "The world's fastest" newly released, has 376 MB cache per cpu. Yes, almost half a Gigabyte. And it runs at 5.26GHz.
And the z196 is dog slow. You need five or more, z196 cpus to match one Nehalem-EX.
On the other hand, Niagara T3 has in total 6MB cache, and it has several world records. In other words, Cache is not king - if you know what you are doing. You dont need all that cache to get good performance, which is evidenced by T3.
File under: HP, Itanium, dead horse, flog.
I thought e-Bay was the major Itanium vendor now?
Intel on Itanium 9300 cache sizes
I realise Peter Hawkins is spot on and that unfortunately for HP, AMD64 killed IA64 a few years ago, but until HP BCS do a Proliant port of the OSes that HP BCS customers still need and still pay for (HP/UX, NSK, VMS), Itanic lives on on life support. For now.
So, for the record, here is what Intel say about the Itanium 9300 cache sizes (retyped by hand because the Intel PDF is cut/paste protected and i cba breaking it):
6MB L3 cache
512KB L2 I-cache
256KB L2 D-cache
Latency 1 cycle L1, 5-7 cycles L2.
Peak main memory bandwidth 34GB/s (realistic bandwidth? See McCalpin and weep, if they ever get published - but the brochure obviously doesn't say that).
Joke? Itanium, and HP's loyalty to it. Your customers want the software, stupid. Not, in general, the IA64.
"The Bulldozer module will take up 30.9mm square of area"
There's a huge difference between 30.9mm square and 30.9 square mm. I think the Bulldozer is the latter.
mm square != square mm
Title says it all.
Best koke I've heard this week...
"The most interesting chip for commercial servers that will be detailed at the ISSCC event could turn out to be the "Poulson" Itanium processor."
Interesting. Itanium. ROFL!
... reminds me of Dan Simmon's "Hyperion"
... in his Hyperion / Endymion books, "Poulsen treatments" were used to prolong lives.
Phonetically close enough for me. If I remember the books correctly, overapplication of the technique lead to people becoming blue in the face.
Who's buying this kit? Could you tell us why? Ta.
"Who's buying this kit? Could you tell us why?"
Part of the answer is not difficult.
There are only two possibilities:
1) People that may not care about the hardware but need OSes that are only available on IA64. These are HP/UX (other Unixes are available) and ex-Tandem's NonStop Kernel and ex-DEC's VMS (alternatives to NSK and VMS are not readily available).
2) People that may not care about the OS but do need more processors or more memory or more IO in a single system than they can get on the largest currently available x86-64 boxes (eg largest current high end Proliant). This is a tiny tiny tiny market for big big big boxes and it is increasingly being eaten into by near-commodity x86-64 hardware.
Working out what kind of customer fits this description is a bit trickier.
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