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SGI preps supers for future Intel chips

To Itanium or not to Itanium

As Quiet as Grass Growing

On the Altix 4700 server line, which is also a blade-style architecture but one employing SGI's NUMAflex clustering technology to create a global memory space for the blades, Brown was quiet as the grass growing on a hot summer day when pressed about who QuickPath Interconnect might give SGI different processor options. Meaning, for instance, that future Altix 4700 machines might support Nehalem chips and not Itaniums, or both, or maybe just the future quad-core Tukwilas, which are also due to ship in early 2009. "We are committed to global shared memory and moving forward with new processors," Brown said with a smile.

That could mean anything, of course.

Considering all of the tuning that SGI has done for Linux on Itanium, it is hard to believe that the future Altix machines (presumably the 4800s) won't support Tukwila. But given the presumably cheaper flops in a Nehalem chip, it is equally hard to believe such future machines would not offer Nehalems as an option, either. That global shared memory (not quite as tightly coupled as the memory in an SMP server, but certainly looking more like a single memory space to HPC applications than does a parallel Linux cluster) is very useful to a certain class of customers, and they will pay a premium for it. Which would seem to argue that if Nehalems are cheaper and can be put into kickers to the Altix 4700s, SGI might possibly boost its bottom line.

While a rack of Altix ICE machines can deliver 3 TB of distributed memory per rack, the Altix boxes can bring 1,024 Itanium cores to bear on a single Linux instance with a globally addressable memory, and SGI has customers with over 8,000 processors and a global shared memory expanding up to 20 to 30 TB; the architecture, says Brown, scales to 128 TB of global shared memory today.

All that said, you can imagine that SGI would like to cut some other costs, quite possibly by converging the Altix 4700 NUMAflex and Altix ICE lines. Imagine a line of Nehalem-based machines that offered the option of the InfiniBand interconnect used in the ICE products and another line that had NUMAflex as an option, allowing the global shared memory of the Altix 4700. One might even imagine that the networking aspects of these blades could be made modular (like compute, I/O, and memory are in the ICE products already), so a blade could be converted from one style of computing to the other. Or, because of the common QPI socket for Tukwila and Nehalem, from one processor type to another. And if that were not possible or economically feasible, then imagine including both native InfiniBand and NUMAflex ports on a single board to offer both styles.

SGI has lots of options, technically, but economically speaking, it is limited. SGI can only afford to create products that will sell and sell now. It will be interesting to see what SGI does. The one thing that SGI doesn't seem inclined to do is embrace the Opteron processors from Advanced Micro Devices - a position it has taken since the company moved off its own MIPS chips and Irix operating system and embraced Itanium and Linux. ®

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