Amdahl Unveils Eight-Way Xeon

While much of the industry is patiently awaiting standardized building blocks to emerge from Intel Corp. to construct eight-way Xeon-based Windows NT servers, Amdahl Corp. (Sunnyvale, Calif., <A HREF="http://www.amdahl.com/">www.amdahl.com</A>) is trying to leapfrog the competition.

• 09/23/1998

Built in collaboration with Amdahl parent company Fujitsu Ltd., the server uses a Fujitsu technology called the Synfinity interconnect to marry two Xeon quad processor blocks into a single, composite system. The Synfinity interconnect technology is based on a nonuniform memory architecture (NUMA) design.

Called the Fujitsu Teamserver M831I, the machine will include up to eight Pentium II Xeon processors and 10 64-bit PCI slots, and can support up to 16 GB of memory. The machine will use two four-processor chassis that will be interconnected to create an eight-way system.

The Synfinity interconnect bridges the system bus of each quad processor block through a special connector designed into the processor boards by Intel specifically for Fujitsu’s design. "The quad boards are based around a special variant of the [Intel] Aspen board set," says Jeff Broughton, Amdahl manager of server marketing. Broughton says the variation is largely limited to the interconnect adapter, which he describes as being "literally like a fifth processor."

As recent as 9 months ago, there were multiple technologies vying for dominance in the above-four-way Pentium server market. But most contenders have fallen by the wayside -- or have been acquired by Intel. One year ago Intel, acquired SMP technology provider Corollary Corp. (Irvine, Calif., www.corollary.com), and then early this year snapped up the OctaScale SMP engineering team from NCR Corp. (Dayton, Ohio, www.ncr.com), leaving competitor Axil Computer Corp. (Concord, Mass.) in a precarious position. In June, Axil’s primary source of funding, Hyundai America, pulled the plug on funding for Axil, forcing the company to discontinue new development. Other vendors such as Unisys Corp. (Blue Bell, Pa., www.unisys.com) have marketed SMP designs based on their own technology.

Axil’s design features the Adaptive Memory Crossbar, a technology that was publicly endorsed by Hewlett-Packard Co. and Data General Corp. (Westboro, Mass., www.dg.com) earlier this year. However, the general market has failed to broadly embrace eight-way designs of any type because performance scaling of both the hardware designs and Windows NT itself has throttled potential performance gains that eight-way systems should deliver.

The NUMA-like design that Amdahl/Fujitsu is using bears similarities to other NUMA designs that have been widely discussed as potential solutions for achieving scalable designs for Pentium servers, but few such designs have been successfully implemented for Windows NT. NUMA systems, however, have been successfully marketed by offered by companies such as Sequent Computer Systems Inc. (Beaverton, Ore., www.sequent.com) running variations of Unix. In the past, Sequent has announced plans to offer NUMA systems running Windows NT -- and has publicly demonstrated NUMA system running Windows NT -- but has yet to make such systems available for purchase.

Amdahl maintains that the Synfinity interconnect technology is faster and more efficient than other NUMA technologies. Broughton says the interconnect functions at 800 MBps per direction, for a net total bandwidth of 1.6 GBps. He says this leads to 1 microsecond of bus latency. Other NUMA architectures can have as much as 5 microseconds of latency. The company says it has not conducted any performance testing on the eight-way configurations and is unable to release any performance data.

Rich Partridge, vice president of parallel open systems hardware at consultancy D.H. Brown Associates Inc. (Port Chester, N.Y. www.dhbrown.com), says of the Amdahl/Fujitsu system, "I think their design looks to have high bandwidth but, probably much more importantly, low latency. Therefore, they may well have something that is almost symmetric." The advantage, says Partridge, is that the low latency makes it easier for applications to scale over eight CPUs without any system tweaking, so that applications may not really need to be aware of the nonuniformity. "[The Amdahl/Fujitsu system] holds some great promise," he says.

Partridge adds, "The proof of the pudding, of course, is benchmark performance on a variety of different applications."

Unlike other nonuniform designs, the Amdahl Synfinity machines can run out-of-the-box Windows NT Server 4.0 Enterprise Edition. Other interconnect architectures often have required a customized hardware abstraction layer beneath the core operating system to enable use of eight CPUs.

Amdahl’s Broughton contends the Synfinity architecture not only gives Amdahl a faster time to market than competitors using Intel’s Corollary-developed interconnect technology, but it also will be cheaper. Broughton says a two-chassis, four-processor system will cost less than $40,000, while a fully populated eight-way system with 4 GB of memory will cost more than $100,000.