Apparently Intel and AMD don’t care about poor analysts trying to get their content completed by the end of the quarter, as evidenced by their decision to launch major server processor refreshes (AMD, Intel) on consecutive days this week. Needless to say there has been a vast amount of coverage from web pundits already, so I’m not going rehash it in detail.
Instead I’m going to focus on things that should matter to anybody buying servers this year. First, lets look at Intel’s Xeon 75xx and 65xx processors with respect to:
- Virtualization performance
- Memory subsystem
- System reliability
- Scale up
I’ll look at the AMD Opteron 6000 in a later blog.
Virtualization Performance
Virtualization is one of the few workloads that really make sense on these new processors, and judging by the numbers, they really do deliver. Using VMware’s VMmark benchmark, Intel claims a top score of 71.85 @ 49 tiles using 32-cores (4 x 8-core processors) on an IBM System X3850 X5. To put that in perspective, the previous best 32-core result topped out at 31.56 @ 21tiles on HP ProLiant DL785 using 8 x 4-core AMD processors. The result also trounced a 64-core result (48.23 @ 32 tiles) using 16 of the previous generation Intel XEON processors. That’s a hugely impressive result for a 4-socket system!
Memory Subsystem
This release drives the final nail into Intel’s aging “Front Side Bus” (FSB) memory architecture that dates back the mid-1990s. The FSB architecture had all the processors connected to a common memory controller (AKA “Northbridge”) so that each processor competed with its peers for access to a common pool of memory, thus becoming a bottleneck for performance. The new processors have integrated memory controllers supporting up to 16 memory DIMMs for a total of 64 DIMMs on a 4-socket server (512 GB with 8GB DIMMs), or 32 DIMMs on a 2-socket server ( 256 GB with 8 GB DIMMs).
System Reliability
In the past, x86-based servers have have used a unsophisticated approach to error handling; tell the operating system that something horrible happened and keel over in a heap on the floor. The new Xeons take a very different approach that allows the hardware and operating system to react in a much more flexible way to errors. For example if an unrecoverable memory error occurs, the operating system can look at the error and simply map that memory location out of use, or kill the process (or virtual machine) that is using the affected memory location. In effect, Intel has blurred the line between it’s own high-end Itanium architecture and Xeon, which is good for Xeon, but not so good for Itanium.
Scale Up
The new Xeon architecture can be used to build 8-socket servers with off-the-shelf components (sometimes referred to as a “glue less design”). But they don’t stop at sockets, the Xeon 7500 family in combination with third-party developed memory hubs is designed to support configurations as large as 256 sockets (4096 threads) with 16 TB of memory! The combination of a highly scalable architecture and high system reliability has the potential to put commodity server architectures into direct competition high-end RISC architectures. For a glimpse of where the future of scale up architectures may lie, see SGI’s Altix UV announcement.
Posted by: Nik Simpson
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