Years ago, Dave Patterson remarked that most server innovations were coming from the mobile device world. He’s right. Commodity system innovation is driven by volume and nowhere is there more volume than in the mobile device world. The power management techniques applied fairly successfully over the last 5 years had their genesis in the mobile world. And, as processor power efficiency improves, memory is on track to become the biggest power consumer in the data center. I expect the ideas to rein in memory power consumption will again come from the mobile device world. Just as Eskimo’s are reported (apparently incorrectly) to have 7 words for snow, mobile memory systems have a large array of low power states with subtly different power dissipations and recovery times. I expect the same techniques will arrive fairly quickly to the server world.

ARM processors are used extensively in cell phones and embedded devices. I’ve written frequently of the possible impact of ARM on the server-side computing world.

· Linux/Apache on ARM Processors

· ARM Cortex-A9 SMP Design Announced

· Very Low-Cost, Low-Power Servers

· NVIDIA Project Denver: ARM Powered Servers

ARM remain power efficient while at the same time they are rapidly gaining the performance and features needed to run demanding server-side workloads. A key next step was made late last year when ARM announced the ARM V8 architecture. Key attributes of the new ARM architecture are:

· 64 bit virtual addressing

· 40 bit physical addresses

· HW virtualization support

The first implementation of the ARM V8 architecture was announced the same day by Applied Micro Devices. The APM design is available in an FPGA implementation for development work this month and is expected to be in final system-on-a-chip form in 2H2012. The APM X-Gene offers:

· 64bit addressing

· 3 Ghz

· Up to 128 cores

· Super-scalar, quad issue processor

· CPU and I/O virtualization support

· Out of order processing

· 80 GB/sec memory throughput

· Integrated Ethernet and PCIe

· Full LAMP software stack port

APM X-Gene announcement:

· Press Release: AppliedMicro Showcases World’s First 64-bit ARM v8 Core

· Slides: Applied Micro Announces X-Gene

More ARM and low power servers reading:

· ARM V8 Press Release:

· AnandTech:

· Ars technica:

· CIDR Paper on low power computing:

· The Case for Energy Proportional Computing:

· ARM V8 Architecture:

In the 2nd half of 2012 we will have a very capable, 64bit, server-targeted ARM processor implementation available to systems builders.


James Hamilton



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