From nothing more than an outlandish speculation, the prospects for a new entrant into the volume Linux and Windows server space have suddenly become much more concrete, culminating in an immense buzz at CES as numerous players, including NVIDIA and Microsoft, stoked the fires with innuendo, announcements, and demos.
Consumers of x86 servers are always on the lookout for faster, cheaper, and more power-efficient servers. In the event that they can’t get all three, the combination of cheaper and more energy-efficient seems to be attractive to a large enough chunk of the market to have motivated Intel, AMD, and all their system partners to develop low-power chips and servers designed for high density compute and web/cloud environments. Up until now the debate was Intel versus AMD, and low power meant a CPU with four cores and a power dissipation of 35 – 65 Watts.
The Promised Land
The performance trajectory of processors that were formerly purely mobile device processors, notably the ARM Cortex, has suddenly introduced a new potential option into the collective industry mindset. But is this even a reasonable proposition, and if so, what does it take for it to become a reality?
Our first item of business is to figure out whether or not it even makes sense to think about these CPUs as server processors. My quick take is yes, with some caveats. The latest ARM offering is the Cortex A9, with vendors offering dual core products at up to 1.2 GHz currently (the architecture claims scalability to four cores and 2 GHz). It draws approximately 2W, much less than any single core x86 CPU, and a multi-core version should be able to execute any reasonable web workload. Coupled with the promise of embedded GPUs, the notion of a server that consumes much less power than even the lowest power x86 begins to look attractive. But…
Intel today officially announced the first products based on the much-discussed Sandy Bridge CPU architecture, and first impressions are highly favorable, with my take being that Sandy Bridge represents the first step in a very aggressive product road map for Intel in 2011.
Sandy Bridge is the next architectural spin after Intel’s Westmere shrink of the predecessor Nehalem architecture (the “tick” in Intel’s famous “tick-tock” progression of architectural changes followed by process shrink) and incorporates some major innovations compared to the previous architecture:
Minor but in toto significant changes to many aspects of the low-level microarchitecture – more registers, better prefetch, changes to the way instructions and operands are decode, cached and written back to registers and cache.
Major changes in integration of functions on the CPU die – Almost all major subsystems, including CPU, memory controller, graphics controller and PCIe controller, are now integrated onto the same die, along with the ability to share data with much lower latency than in previous generations. In addition to more efficient data sharing, this level of integration allows for better power efficiency.
Improvements to media processing – A dedicated video transcoding engine and an extended vector instruction set for media and floating point calculations improves Sandy Bridge capabilities in several major application domains.
I’ve recently had the opportunity to talk with a small sample of SLES 11 and RH 6 Linux users, all developing their own applications. All were long-time Linux users, and two of them, one in travel services and one in financial services, had applications that can be described as both large and mission-critical.
The overall message is encouraging for Linux advocates, both the calm rational type as well as those who approach it with near-religious fervor. The latest releases from SUSE and Red Hat, both based on the 2.6.32 Linux kernel, show significant improvements in scalability and modest improvements in iso-configuration performance. One user reported that an application that previously had maxed out at 24 cores with SLES 10 was now nearing production certification with 48 cores under SLES 11. Performance scalability was reported as “not linear, but worth doing the upgrade.”
Overall memory scalability under Linux is still a question mark, since the widely available x86 platforms do not exceed 3 TB of memory, but initial reports from a user familiar with HP’s DL 980 verify that the new Linux Kernel can reliably manage at least 2TB of RAM under heavy load.
File system options continue to expand as well. The older Linux FS standard, ETX4, which can scale to “only” 16 TB, has been joined by additional options such as XFS (contributed by SGI), which has been implemented in several installations with file systems in excess of 100 TB, relieving a limitation that may have been more psychological than practical for most users.
In October, with great fanfare, the Open Data Center Alliance unfurled its banners. The ODCA is a consortium of approximately 50 large IT consumers, including large manufacturing, hosting and telecomm providers, with the avowed intent of developing standards for interoperable cloud computing. In addition to the roster of users, the announcement highlighted Intel with an ambiguous role as a technology advisor to the group. The ODCA believes that it will achieve some weight in the industry due to its estimated $50 billion per year of cumulative IT purchasing power, and the trade press was full of praises for influential users driving technology as opposed to allowing rapacious vendors such as HP and IBM to drive users down proprietary paths that lead to vendor lock-in.
Now that we’ve had a month or more to allow the purple prose to settle a bit, let’s look at the underlying claims, potential impact of the ODCA and the shifting roles of vendors and consumers of technology. And let’s not forget about the role of Intel.
First, let me state unambiguously that one of the core intentions of the ODCA, the desire to develop common use case models that will in turn drive vendors to develop products that comply with the models based on the economic clout of the ODCA members (and hopefully there will be a correlation between ODCA member requirements and those of a wider set of consumers), is a good idea. Vendors spend a lot of time talking to users and trying to understand their requirements, and having the ODCA as a proxy for the requirements of a lot of very influential customers will be a benefit to all concerned.
I have been working on a research document, to be published this quarter, on the impact of 8-socket x86 servers based on Intel’s new Xeon 7500 CPU. In a nutshell, these systems have the performance of the best-of-breed RISC/UNIX systems of three years ago, at a substantially better price, and their overall performance improvement trajectory has been steeper than competing technologies for the past decade.
This is probably not shocking news and is not the subject of this current post, although I would encourage you to read it when it is finally published. During the course of researching this document I spent time trying to prove or disprove my thesis that x86 system performance solidly overlapped that of RISC/UNIX with available benchmark results. The process highlighted for me the limitations of using standardized benchmarks for performance comparisons. There are now so many benchmarks available that system vendors are only performing each benchmark on selected subsets of their product lines, if at all. Additionally, most benchmarks suffer from several common flaws:
They are results from high-end configurations, in many cases far beyond the norm for any normal use cases, but results cannot be interpolated to smaller, more realistic configurations.
They are often the result of teams of very smart experts tuning the system configurations, application and system software parameters for optimal results. For a large benchmark such as SAP or TPC, it is probably reasonable to assume that there are over 1,000 variables involved in the tuning effort. This makes the results very much like EPA mileage figures — the consumer is guaranteed not to exceed these numbers.
I recently spent a day with IBM’s x86 team, primarily to get back up to speed on their entire x86 product line, and partially to realign my views of them after spending almost five years as a direct competitor. All in all, time well spent, with some key takeaways:
IBM has fixed some major structural problems with the entire x86 program and it perception in the company – As recently as two years ago, it appeared to the outside world that IBM was not really serious about x86 servers. Between licensing its low-end server designs to Lenovo (although IBM continued to sell its own versions) and an apparent retreat to the upper-end of the segment, it appeared that IBM was not serious about x86 severs. New management, new alignment with sales, and a higher internal profile for x86 seems to have moved the division back into IBM’s mainstream.
Increased investment – It looks like IBM significantly ramped up investments in x86 products about three years ago. The result has been a relatively steady flow of new products into the marketplace, some of which, such as the HS22 blade, significantly reversed deficits versus equivalent HP products. Others followed in high-end servers, virtualization and systems management, and increased velocity of innovation in low-end systems.
Established leadership in new niches such as dense modular server deployments – IBM’s iDataplex, while representing a small footprint in terms of their total volume, gave them immediate visibility as an innovator in the rapidly growing niche for hyper scale dense deployments. Along the way, IBM has also apparently become the leader in GPU deployments as well, another low-volume but high-visibility niche.