In-Depth

Sun’s UltraSPARC T1 Redefines the Rules of the Game

UltraSPARC T1 is a marvelous achievement, to be sure—but will its cutting edginess translate into market success?

• By Stephen Swoyer
• 12/13/2005

Almost three years ago, Sun Microsystems Inc. outlined a next-generation chip roadmap that surprised many industry watchers. The company—then a laggard in the race to pack more than one processor core on a single chip die—promised to radically up the ante in the multi-core chip stakes.

In just 36 months, Sun officials promised, the company would produce an eight-core chip (code-named “Niagara”) that would also incorporate aggressive multi-threading capabilities. This was nothing short of astonishing.

At the time, Sun was trailing IBM Corp. and Hewlett-Packard Co. in the race to dual-core chipdom—IBM’s Power4 processor was the first dual-core chip from a prominent systems vendor, and HP’s PA-RISC 8800 chip had also gone dual-core. What’s more, IBM was prepping a quad-core version of its Power chip, with significantly enhanced multithreading capabilities. Sun’s UltraSPARC platform—plagued by delay after delay—was still uni-core.

Last week—and several months early—Sun announced two new servers based on the fruits of the Niagara project. As promised, Sun’s new SunFire T1000 and T2000 servers are ambitious multi-core designs. They’re powered by a single UltraSPARC T1 microprocessor (Sun’s productized name for the former “Niagara” technologies), which is, in turn, populated with eight discrete processor cores running at 1.2 GHz each. The UltraSPARC T1 can process as many as 32 threads simultaneously.

But that’s not all. Sun’s UltraSPARC T1 design consumes significantly less power and dissipates much less heat than competitive designs from IBM, HP, Intel Corp., and Advanced Micro Devices (AMD) Inc. It also outperforms comparable processors from all three vendors in most common benchmarks (e.g., SPECweb2005 and SPECjAppServer2004). What’s more, Sun has priced both the T1000 and the T2000 to move: the former (a 1U system) starts at $2,995; the latter (a 2U system) at $7,995.

For the record, the UltraSPARC T1 is able to accomplish all of this while consuming just 72 watts. (This is 12 watts higher, however, than Sun’s original goal.) For thread-intensive applications (e.g., Web servers, J2EE application servers, some online transaction processing requirements) in which performance and data-center rack space are at a premium, that makes for an all-but-unbeatable value proposition.

Analysts are suitably impressed. Nathan Brookwood, a principal with microprocessor consultancy Insight64, has covered the microprocessor beat for more than a decade and all but gushes over Sun’s new chip. “The new Sun systems handily outperform comparably configured, albeit more expensive Power 5+, Xeon and Itanium configurations on standard benchmarks,” he writes. “But performance is only half the story. The T1000 and T2000 consume far less power and dissipate far less heat than those Power 5+, Xeon and Itanium systems. This gives Sun a dramatic advantage in terms of performance per Watt, a metric of increasing importance to IT managers struggling to handle growing workloads in datacenters that have already maxed out their power and HVAC resources.”

As Brookwood notes, Sun’s eight-core servers effectively demolish competitive systems on a performance-per-watt basis. In this respect alone, Brookwood argues, Sun appears to have pulled off a viability makeover.

“Sun's systems beat competitive offerings by factors of four or five on this key metric, a truly stunning improvement over the prior state of the art. If these new systems cannot reignite growth of Sun's SPARC-based systems business, it's hard for Insight 64 to imagine what could.”

Even veteran industry watcher Charles King, formerly of the Sageza Group (nee Zona Research), and now the principal of his own enterprise-computing consultancy, Pund-IT Research, gives Sun its due. In the past, King has been highly critical of the Unix giant’s missteps, but this time around he sees a considerable upside to the UltraSPARC T1 release.

“Sun had an awful lot to say about its T1-based servers, and with good reason,” King writes, adding that the UltraSPARC T1 “represents a strategic flag in the ground for the company’s future aspirations.” King is particularly intrigued by the new metric (Space, Wattage, and Performance, or SWaP) that Sun uses to measure power consumption and data-center performance. “Sun’s new SWaP metric offers an interesting approach to a highly complex subject, but its actual value is unclear. If SWaP finds an audience outside of Sun, it could spur a broader dialogue on the subject of datacenter energy issues.”

Indeed, Sun’s SWaP metric amounts to an altogether new pitch for the former Niagara, which was once touted as a massively parallel chip optimized for “throughput computing”—or network (HTTP server, J2EE application server) workloads. These days, analysts say, Sun is putting a very different spin on Niagara. “Sun’s new pitch for [UltraSPARC] T1 … is now less about parallelism and more the IT metric of the moment: performance per watt,” writes Gordon Haff, a senior analyst with consultancy Illumianta, on that company’s Weblog. “As a result, Sun’s wrapped T1 in the flag of ‘eco-responsibility’ and is leading with how much power the 72-watt [79 watt peak] chip can save compared to the mainstream x86 alternatives, which typically run in the 95 to 120 watts range each. Sun is thus deftly building on the themes of its ‘Share’ campaign while plugging into a rapidly developing IT concern.”

Hold Your Horses

Analysts don’t let Sun completely off the hook, however. Pund-IT Research’s King, for example, takes issue with CEO Scott McNealy’s hyperbolic hyping of the UltraSPARC T1’s “9.6 GHz” clock speed. McNealy arrived at that number by multiplying the stock speed of each of the T1’s cores (1.2 GHz) by the total number of cores (eight). King thinks that’s being too clever by half. “McNealy’s claim of the T1’s 9.6 GHz frequency … suggests a novel approach to determining multi-core performance that should send chip watchers scrambling for their calculators,” he comments.

Elsewhere, Sun’s new T1 servers are only as powerful as the software that runs on them. Even though the Unix giant says existing Solaris binaries can run unmodified on the new T1 systems, that doesn’t necessarily mean they’ll be able to take full advantage of Niagara’s aggressive multi-threading capabilities.

“While Sun guarantees binary compatibility for Solaris on T1 and said Solaris applications will run unmodified on the new servers, the company’s vice-president of scalable systems [David Yen] has been quoted as saying that applications ‘must be optimized to work well’ on T1 systems,” King argues. “How much optimization is unclear, but since T1 changes minimum application scalability demands to 32 concurrent threads, a number of programs are likely to require significant redesign.”

Insight64’s Brookwood flags the UltraSPARC T1’s lackluster floating point performance (a consequence, he notes, of the fact that all eight cores share a single FPU) and raises questions about its lack of SMP support. In fact, until Sun ships the successor to Niagara (Niagara 2) in 2007, its T1 Servers will be available only in single-chip configurations (albeit single chips populated with eight 1.2 GHz processor cores). When Sun does deliver Niagara, that chip will feature eight cores (with support for up to eight threads per core)—or 64 threads in all—and dual-processor capabilities as well. That will let Sun’s servers scale to up to 128 cache-coherent threads in a system, Brookwood points out.

But if performance in any of several standard benchmark suites is any indication, Sun appears to have a thoroughbred in the UltraSPARC T1, Brookwood says. More importantly, he argues, UltraSPARC T1 has revitalized Sun—something he admits he (among others) wasn’t sure was possible.

“Before Sun embarked on its throughput computing adventure, we … questioned whether it made sense for Sun to develop its own processors. Its UltraSPARC line offered few advantages with regard to performance or price/performance. Their chips' primary virtue was the ability to run Solaris without the need to recompile and/or reacquire software applications,” Brookwood indicates. “The launch of Sun's new products demonstrates that there is still a place for innovation in the systems business, and that customers are best served when many suppliers are allowed to bring their unique perspectives to the market. It's unlikely that an Intel or an AMD would have pursued the kind of extreme multicore/multi-thread approach Sun pursued, since those suppliers try to leverage their designs across both client and server markets.”