Original URL: http://www.theregister.co.uk/2009/07/21/ibm_power7_details/

IBM lifts the veil on Power7 chips

Promises upgrades from Power6 boxes

By Timothy Prickett Morgan

Posted in Hardware, 21st July 2009 11:49 GMT

With every new server processor generation, there is always the possibility that the chip and its associated chipsets and system components are so different that both the chip and the server platform have to change at the same time. This will not be the case for the Power7 processors due next year, says IBM.

IBM is in no hurry to ship Power7 chips and the systems that use them. Not with so many other products being delayed. Intel's "Tukwila" quad-core Itaniums have been pushed back until the first quarter of 2010 and probably will not show up in systems until the middle of 2010. While its eight-core "Nehalem EX" (sometimes called "Beckton") Xeon-class processors are not going to be ready until late this year and probably not into systems until the first quarter of 2010.

Advanced Micro Devices is expected to get its 12-core "Magny-Cours" Opterons and their G34 chipset out the door in the first quarter of next year, but it is unclear who will be building big bad boxes out of them. And the fate of the 16-core "Rock" UltraSparc-RK chip was far from certain even before Sun Microsystems was slated to be eaten by software giant Oracle, and the rumor back in mid-June was that Sun had already killed off the Rock chip ahead of the Oracle deal. Fujitsu may have some speed bumps for its quad-core Sparc64-VII processors, which are sold in Solaris systems by Sun and Fujitsu, but it is not expected to get its own eight-core "Venus" Sparc64-VIII into the field until 2010 or 2011.

So IBM is not feeling the pressure from its competition in the midrange and high-end of the server racket to say squat about Power7. But its Power Systems customers, having seen so many other chips in the market delayed in the past year or more, are looking for a little confirmation that the Power7 chip is on track.

They also want to know whether or not the Power7 chips will be available to them through an upgrade process or if they will have to do a push-pull box swap to get to the new machine. In this economic environment, when Power server customers are not sure when the next thing will be available, what kind of performance it will offer, and what kinds of upgrade paths will be available, customers are not inclined to spend now. Since a new generation of chips and servers almost always means a boost in bang for the buck, it is smarter to wait it out.

IBM, of course, doesn't want customers to wait it out. It wants shops to buy Power6 or Power6+ systems today because it needs to make its numbers this quarter and next. And so Scott Handy, vice president of marketing and strategy for the Power Systems division, says that customers who buy Power 570 machines (which have up to 16 Power6 cores or up to 32 cores Power6+ cores) and Power 595 machines (which have up to 64 of the Power6 cores) will be able to upgrade to Power7 machines in such a way that they can preserve their serial numbers on their boxes.

Such an upgrade path is important because accounting rules require that an upgrade that preserves serial numbers, and therefore does not subject the box to immediate depreciation of any extant value in the box, keep a fairly large amount of the original box as part of the upgrade. According to Handy, the Power 595 machine, which is a big SMP box with NUMA-ish cache coherency, will be upgradeable by swapping out processor motherboards (what IBM calls books) with Power6 chips and swapping in Power7 boards.

The Power 570 has a slightly different architecture, with processor cards plugging into a chassis and several chassis being linked together with NUMA-ish chipsets and presenting a single system image, but Handy says that the way IBM is upgrading Power 570s from Power6 and Power6+ chips to Power7 chips will allow it to legally preserve serial numbers.

This means customers who are buying Power 570s and 595s today know they won't have to ditch these boxes entirely if they need to move to Power7 machines next year or the year after, which means they don't have to write off their investments ahead of their normal depreciation schedule. The guarantee of upgrade paths also means that customers had better take a stab at what they think pricing will be on Power7 boxes and make sure they get steep discounts on the current Power Systems machines, because they can bet IBM isn't going to give away upgrades to Power7 chips.

The neat trick with upgrades this time around is that the PowerVM hypervisor that logically partitions Power Systems machines has a feature called Live Partition Mobility, which will enable customers with two physical servers to move workloads off of one box, upgrade it to Power7 chips, and then move workloads back to partitions running on the new Power7, all without shutting down the running workloads. Customers with only one machine can do the upgrade as part of planned downtime (or they could rent a secondary box from IBM or a reseller just to do the Aztec two-step).

Price cut coming?

In May 2006, after the dual-core Power5+ chips came out late and didn't offer the kind of performance boost customers were expecting and the Power6 chips were pushed out into 2007 instead of their expected fall 2006 launch, IBM offered customers using System p 570 (16 core), 590 (32 core), and 595 (64 core) machines upgrade paths to the future Power6 machines that preserved serial numbers on Power5 and Power5+ boxes. The delays with the Power6 chips and a nine per cent drop in Unix server sales in the first quarter of 2006 also compelled Big Blue to cut prices on Power 590 and 595 machines.

IBM has not cut prices on its current Power6 and Power6+ servers, but if the upgrade guarantee doesn't grease the sales skids, that will be the next move.

In addition to talking about the upgrade path guarantee, Handy also provided a few more details about the future Power7 chip, which will be implemented in a 45 nanometer chip process and which will be manufactured in IBM's East Fishkill, New York, foundry. Back in December 2008, when discussing the "Blue Waters" supercomputer and its data center, IBM had confirmed that Power7 chips would have eight cores.

According to Handy, IBM actually plans to offer Power7 chips with four, six, or eight cores when they begin shipping in systems some time in the first half of 2010. He would not be more precise about the launch schedule, except that it would be a staggered announcement as was the case with the Power5 and Power6 rollouts, starting on a few machines and eventually spanning the line.

The Power7 chips will come with a variety of clock speeds, too, some designed to give the most performance per core and some designed to deliver the most performance per watt. The word on the street last year was that the Power7 chips would clock at between 3 GHz and 4 GHz, but IBM has not confirmed this (even now). Handy also added that the Power7 chips will support up to four threads per core, up from the two threads per core of the Power5 and Power6 generations.

What IBM did say is that depending on the chip, the Power7 variants will offer anywhere from two to three times the performance per watt of a Power6 chip at a given wattage. In the jump from Power5 to Power6 (which was actually two steps including the Power5+), IBM delivered about twice the oomph in the same energy envelope. The jump from Power5+ chips to Power6 chips was more like 50 per cent more oomph by my estimate, and the move from Power6 to Power6+ was more like 15 per cent.

Clearly chips with a plus don't fare well at IBM, since the Power4+ was not much to write home about, either. Anyway, provided that the energy envelope of the Power7 machines remains more or less the same, what this means is that customers can expect two to three times the performance.

IBM also confirmed that the Power7 chips will support DDR3 main memory; Power6 and Power6+ servers use DDR2 memory, and Power5 and Power5+ machines used DDR1. IBM currently uses double data rate InfiniBand links between the Power6 and Power6+ chips out to remote I/O drawers (which it calls 12X I/O), and it is not yet clear if IBM will boost this up to quad data rate InfiniBand with the initial Power7 machines, according to Handy.

Customers using the older Remote I/O drawers and their High Speed Links (IBM's funny name for Fibre Channel peripheral links to external I/O cages) will have to upgrade to 12X I/O before moving to Power7 chips, since Remote I/O will not be supported with Power7 servers as it was with Power6 and Power6+ machines.

On the logical partitioning front, the Power7 machines will be able to host up to 1,000 partitions per system, up from the current maximum of 254 partitions on Power5 through Power6+ machines. I have been told in the past that the Power6 and Power6+ chips could already, in theory, support 1,000 partitions, but for whatever reason IBM did not activate this latent capacity. Presumably the Power7 chips theoretically support something akin to 4,000 partitions on boxes using eight-core chips; IBM didn't say.

Handy said that IBM will patch its AIX 6.1 Unix variant as well as its i 6.1 proprietary operating system so it can run atop the Power7 chips and make use of its features. Some time in 2010, whole new AIX 7 and i 7 operating systems will be delivered by IBM, not only with full Power7 support, but presumably with other capabilities.

IBM plans to talk a bit more about the Power7 chip and server designs at the Hot Chips conference hosted by the IEEE at the end of August at Stanford University. We'll keep you posted. ®