Microsoft Puts X64 Windows to the Dog Food Test

by Alex Woodie

To show the world that the X64 editions of Windows Server 2003 and Windows XP Professional are good to go, Microsoft is using them to run production systems, a process that it euphemistically refers to as "eating your own dog food." At presentations last week at the WinHEC 2005 conference, Microsoft representatives showed how Windows Server 2003 X64 Edition provided a boost to its Web serving infrastructure, and how Windows XP Professional X64 Edition helps developers compile code faster.

Microsoft ushered in a new era of mainstream 64-bit computing last week when it officially launched the new X64 editions of Windows XP and Windows Server 2003 (see "64-Bit Windows Goes Mainstream at WinHEC 2005"). With the capability to run older 32-bit applications as well as applications that have been redeveloped to take advantage of the larger 64-bit address spaces, Microsoft fully expects its X64 editions of Windows to be a hit in the marketplace and to fundamentally change how we use computers.

Like it has for other new products, Microsoft deployed the X64 editions of Windows in-house as part of its own IT operations, as a way of proving to itself, and the world at large, that the software is ready for prime-time. In other words, if you make software, you better like it well enough to use it yourself. And if you make dog food, you better like it well enough to eat it yourself. At the WinHEC 2005 conference last week, Microsoft representatives provided several status reports on its dog food tests.

Clyde Rodriguez, the Microsoft group program manager in charge of the Windows Server 2003 Service Pack 1 and Windows Server 2003 X64 Edition development projects, provided an overview of the capabilities of X64 products, which have been in development for two years.

Rodriquez said the X64 edition of Windows benefited his development team by reducing system build times by 66 percent. What started out with nine-hour build times under 32-bit versions of Windows dropped to just three hours with Windows X64, he says. This improvement has obvious benefits in terms of helping Microsoft's development team to work more efficiently.

(Faster built times could also be one reason why Microsoft has been able to hit its self-imposed launch deadlines recently. While other products, like "Yukon" and "Whidbey" have seen delays recently, we haven't seen an operating system delay in quite a while, and the product launches, including Windows Server 2003 SP1 and Windows Server 2003 X64 Edition and the beta of Windows Server 2003 R2, have been coming fast and furious.)

Microsoft also transitioned to the X64 edition of Windows Server 2003 to run its assorted Web sites. Microsoft maintains an enormous Web presence, with 90 different Web sites, 1,100 databases, and 1,900 different Web applications, according to one of the Web site technicians Rodriquez brought on stage during his presentations. Microsoft's Web presence is among the top five in the world, with 130,000 requests made every second and a network connection able to handle outflows of 40GB per second.

However, the 2GB virtual memory limit imposed by the 32-bit X86 architecture posed a performance problem for the Microsoft Web serving team. (And it wasn't about to switch to a higher-performing RISC architecture. This is dog-fooding, remember.) The team tried flipping a switch in the X86 version of Windows Server 2003 that would allow the operating system kernel to utilize an extra 1GB of virtual address space, but that didn't do much to help. (In fact, it was a "disaster," the tech said.)

With the X64 version of Windows Server 2003, applications and the operating system have twice as much memory, or 4GB, to work with. While this requires an investment in more physical memory to get the necessary benefits, they were well worth it to Microsoft and its Web hosting team.

Microsoft provided details of how it transitioned one four-way server running 2.0GHz X86 processors with 4GB of memory to a four-way server running 2.2GHz X64 processors with 16GB of memory. While the higher processing speed makes this less of an apples-to-apples comparison than is ideal, the results probably more than make up for it.

One benefit of the 64-bit architecture is servers that can make much better use of memory, which can have the side affect of alleviating bottlenecks in other places. "No matter how much RAM you have, once you have exhausted the kernel of virtual address space, you're pretty much done," said Costin Hagiu, the leader of the testing team for Microsoft Terminal Services, in another session.

In the case of Microsoft's four-way Web server, the processors were the bottleneck. With the capability to utilize the bigger address spaces, CPU utilization decreased from 65 percent to 35 percent, and response times for end users increased dramatically as a result.