Printer Friendly

AMD's Opteron aims at Itanium in 64-bit battle.

Industry history buffs know one of the singular lessons of the microprocessor market: x86 compatibility trumps all. Over the last 30 years, many architectures have tried to unseat Intel's king--and not one has succeeded. But what if a company could figure out a way to use Intel's own architecture against it? What if there was a way to provide a future of full application compatibility while Intel attempted to lure customers to a completely new chip architecture?

In the topsy-turvy world of the microprocessor, such an unlikely scenario has finally come to pass, thanks to Intel's chief rival, AMD.

In the spring, Advanced Micro Devices announced Opteron, and AMD is now officially trying to take advantage of Intel's questionable Itanium development decisions to grab a slice of the lucrative enterprise server processor market. According to IDC, 85 percent of servers sold in the first half of 2002 in the U.S. used Intel processors; Sun and other RISC vendors grabbed 11 percent, while AMD trailed with just 4 percent.

The Opteron chip, the first microprocessor to natively support both 32- and 64-bit applications, represents both an enormous challenge for the struggling chip maker (the company has been losing money for years) and a significant challenge to Intel, the world's biggest chip maker and the OEM with a stranglehold on the desktop market--and large market share in the enterprise as well. AMD's 64-bit Athlon, announced with Opteron, is the industry's first foray into 64-bit computing for the desktop. Opteron should be shipping systems by the time you read this, with Athlon 64 available in September.

Opteron represents a completely new server option for enterprise customers. The chip offers the ability to run both existing (and new) 32-bit applications while at the same time adopting more advanced 64-bit software as it becomes available. Opteron's versatility is in marked contrast to offerings from Intel: either the Xeon processor for 32-bit apps or the newer (and somewhat slow-to-be-adopted) Itanium architecture for 64-bit software. (RISC-based chips from Sun and IBM have offered 64-bit support for several years.)

While few doubt that the software industry is destined to evolve to 64 bits, evolution is a long, slow process. As the lukewarm reception for Itanium has demonstrated, 64-bit applications remain scarce--and Intel had that processor under development with Hewlett-Packard for 10 years before its introduction.

In direct contrast to Intel's two-pronged development approach, AMD long ago decided that a processor with native dual (simultaneous 32and 64-bit x86) application support would be more appealing to enterprises unsure about making the financial jump to lightspeed. AMD claims that since 32-bit applications run under emulation on Itanium, performance of these same apps will be better under Opteron. The chip maker has even indicated that 32-bit apps perform better on Opteron than on Xeon, which is of course a native 32-bit architecture (more on this following). Intel rejects these assertions and, in any case, such claims remain to be tested under real-world conditions.

While AMD has announced numerous development deals with Linux OEMs (SuSe, RedHat, UnitedLinux) to tune that operating system for Opteron, development on porting Linux to Itanium by anyone other that Intel seems to be waning; even IBM has scaled back its Linux-on-Itanium development efforts. Thus, it was perhaps not coincidental that at the Opteron launch event, IBM officials indicated that the company will be offering a new server with AMD's chip, though no specifics were given.

Putting even more pressure on Intel, Microsoft announced that it plans to release versions of Windows XP and Windows Server 2003 tuned for Opteron, and AMD has (justifiably) used the announcement to try to persuade large system OEMs (like IBM) to support Opteron.

Inside Opteron

Like Itanium, Opteron's 64-bit memory addressing eliminates one of the largest bottlenecks in highly processor-intensive applications: the limit on physical memory. 32-bit applications can address a maximum of only 4GB of RAM. According to AMD's Opteron documentation, the new processor's 40-bit physical and 48-bit virtual addressing remove this limitation, permitting up to 1 Terabyte of physical memory space and 256TB of virtual memory addressing space.

Opteron also includes multiprocessor support out of the box. AMD says the processor architecture directly supports 18 Opteron processors in a glueless (that is, requiring no chipset support) multiprocessor configuration. A platform can support an unlimited number of Opteron processors in a multiway configuration with external/additional chipset support. Using AMD's HyperTransport technology (see the May 2001 issue of CTR at for a full discussion), the Opteron architecture is designed to support up to three links, which can provide up to 19.2GB/sec (6.4GB/sec each) peak bandwidth. The processor will be fabricated using .13 micron silicon-on-insulator technology and support PC1600, PC2100 and PC2700 DDR memory. Opteron processor models 240, 242 and 244 for up to 2-way servers are shipping now. Opteron processors in the 800 series for up to 8-way servers were expected by early May. AMD expects that Opteron processors in the 100 series for 1-way servers will be available in 3Q03. Prices for the 200 serie s start at $283 each, in lots of 1,000.

According to AMD, Opteron's "x86-64" architecture extends the standard x86 instruction set by adding a new processing mode called "long mode?' Long mode is enabled by a global control bit called LMA (for Long Mode Active). When LMA is disabled, the processor operates as a standard x86 processor, and is compatible with all existing 16- and 32bit operating systems and applications. When Long Mode is activated (LMA = 1) the 64-bit processor extensions are enabled. This allows the system to auto configure according to the capabilities of the machine and the processor.

Long Mode consists of two sub modes: 64-bit mode and compatibility mode. The new modes are encoded using two flags in the code segment descriptor. The first flag is the existing "D" bit that controls the size of operands. A second bit called the "L" bit, a previously unused bit (bit 53) in the CS descriptor, is used for determining if specific applications are 64-bit enabled or are run in compatibility mode.

If long mode is active, CS.L = 1, and CS.D = 0, the processor is then set to run in 64-bit mode. With this encoding, default operand size is 32 bits and default address size is 64 bits. Using instruction prefixes, the default operand size can be overridden to 64 bits or 16 bits, and the default address size can be overridden to 32 bits.

If long mode is active and CS.L=0 then the processor is set to run m compatibility mode. Compatibility mode maintains binary compatibility with applications written in 16- and 32-bit x86 modes. An operating system running natively in Long Mode can run existing 16- and 32-bit applications by simply clearing the L bit in the code segment descriptor of the applications.

The Opteron architecture also eliminates the front-side bus--often called the northbridge. Opteron embeds functions of the northbridge chipset into the CPU itself, including the memory controller. Since in Opteron the built-in memory controller operates at processor frequency, AMD says the clock frequency of the processor can be considered the frequency of its front-side bus. How much of this claim is part and parcel of AMD's long-standing strategy of not competing in the race-for-megahertz game with Intel remains a matter of opinion. Regardless, AMD claims that Opteron is the highest performing 2P and 4P server processor available, according to industry-standard benchmarks. In TPC-C benchmark tests, AMD says, Opteron achieved performance up to 1.4 percent greater than competing 32-bit server processors. On the Internet-related performance benchmark SPECweb99, the Opteron Model 844 was the first processor in the world to break the 10,000 score.

The Vision

According to a whitepaper outlining the company's long-term strategic vision, AMD's goal with x86-64 is straightforward: an alternative to the total conversion of all systems within an enterprise to a new, non-backward compatible 64-bit instruction set. "AMD processors including x86-64 technology will permit platform suppliers, developers, corporate MIS departments and consumers to transition to 64 bits gradually, while continuing to run 32-bit applications without incurring performance penalties," the paper says. The company posits that by providing a smoother migration path to 64 bit computing than the path offered by Intel, "AMD's strategy is designed to save its customers billions of dollars in software re-development and deployment costs."

How likely is such a scenario? According to a report by Giga Information Group (for a study that AMD commissioned, it should be noted), organizations can derive significant cost savings by gradually adding Opteron-based servers as software is transitioned to 64 bits.

"Based on Giga's research, an organization should consider a server replenishment strategy that includes deploying AMD Opteron processors prior to the need to migrate to 64-bit applications' the report states. "With this strategy AMD Opteron processor-based servers will be able to run existing 32-bit applications while being available to adopt 64-bit applications at the organization's own pace, as hardware, ISV software support and developers' time become available. This migration strategy and binary feature would likely reduce future server costs for an organization adopting the AMD's x86-64 technology, as these AMD Opteron processor-based servers would not have to be discarded and replaced with a 64-bit upgrade."

Nevertheless, the report also notes a number of intangibles that are likely to affect the success of Opteron, including ongoing future support from Microsoft, buy-in and continuing support from enterprise server vendors, and ISV support, particularly the porting of 32-bit applications to 64 bits.

Launch Control

The importance of AMD's Opteron launch to the company's future cannot be overstated: Company CEO Hector Ruiz recently noted that this is the first time in the company's 30-plus year history that AMD has touted a product and its technology so far in advance of introduction. Partnership announcements began appearing a year and a half ago, although the chip launch is about six months behind schedule.

And, indeed, a number of vendors have committed to Opteron support. Of these, the biggest name is surely IBM: Big Blue will offer DB2 version 8 for Linux running on Opteron, as well as the aforementioned server product. Oracle has also announced a forthcoming Opteron version of its popular database software. Other vendors that have announced various levels of support include Intersil, JNI, LSI Logic, Micron, Texas Instruments, VIA, and a number of smaller BIOS component, chip, and interface equipment suppliers. Newisys, a small, two-year old system OEM founded by IBM and Microsoft alums and based in Austin, has committed to building Opteron servers.

Missing from the support list, however, are names like Dell, HP, and Gateway. Without the support of at least one of these OEMs, AMD may have trouble mustering the critical mass needed for the introduction of any new processor. For a recent example of such a situation, AMD need only look to Intel, which is still struggling to get Itanium (now in its second version) into the hands of enterprise customers-even Dell has pulled the chip from its product line, at least for now.

Still, any competition in the server processor market is welcome and, if nothing else, Opteron is sure to keep Intel engineers on their toes. There are even rumors that Intel has a new processor in the wings that deals with 32- and 64-bit code in a fashion similar to Opteron. If AMD's new processor takes off--or if Itanium 2 fails to grab market share--we may yet see such a CPU from Intel. In this vein, at press time Intel had just announced that the company is working with Microsoft to help Redmond create a 32-bit emulation layer for Itanium, called the IA-32 Execution Layer, in Windows. Intel says the new software will increase performance of some 32-bit apps running on Itanium by converting code to 64 bits.

And the race is on.
COPYRIGHT 2003 West World Productions, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2003, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Author:Piven, Joshua
Publication:Computer Technology Review
Geographic Code:1USA
Date:Jun 1, 2003
Previous Article:SMI takes it place in storage annals: SNIA waves storage standard banner.
Next Article:T-rex and Shark both have teeth. (First-In/First Out).

Related Articles
AMD demos prototype 64-bit Microsoft Windows OS running servers.
Covalent and Red Hat developing 64-bit Apache Web server software for future AMD Opteron processors.
Sun Microsystems partners with AMD to provide native support for Java technology on 64-bit AMD Opteron processor for Linux and Windows: high...
AMD announces new AMD Opteron processors, adding more choice and flexibility for leading 32- and 64-bit computing.
AMD intros new players to the high-performance 32- and 64-bit AMD Opteron processor lineup.
AMD Opteron processors power new high-end workstation from Fujitsu Siemens Computers.
AMD Opteron installations see a increase on the newest TOP500 supercomputer list.
AMD drives future of Formula One technology.

Terms of use | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters