HP researcher predicts memory-centric processors

Of microblades and snitches
HP Labs has identified three kinds of server designs each optimized for different kinds of data center workloads. It has also created metrics to match workloads to the right design.

An energy proportional design ramps server performance up or down based on an application's needs. A consolidated design packs multiple jobs into a single system, and a so-called microblade breaks down jobs into tasks that can be handled by multiple low power processors.

HP Labs evaluates server opportunities in low power processors (LP), energy proportionality (EP) and consolidated systems (CONS) using metrics described in part with this diagram.

While they are no panacea for today's power hungry data centers, "low power ARM and Intel Atom processors are valid for a huge part of the market as long as they have a factor of 3-3.5 times the Mips per watt as the alternative," said Ranganathan. "There are places where we do get to this factor," he said.

Companies such as HP are conducting comparative tests of the traditional and low power processors, but not revealing their results. "Things are changing pretty fast with ARM Cortex A9, new Atom chip sets and new Intel Xeon chips coming," he said.

Ranganathan said he expects microblades using low power server processors will fill a real, but limited commercial role in future data centers. One factor that determines the limits of low power server processors is the extent to which underlying algorithms can be split into separate tasks.

"There are some workloads where Atom processors are amazing and some where they aren’t," he said.

Merged communications devices using optical interconnects represent one other piece of the puzzle for tomorrow's servers. For example, Ranganathan envisions a merged network interface card and switch he calls a snitch that could drive increased throughput while consuming less energy than today's separate components.

Within two years such devices could emerge to speed switching and routing of traffic running in virtual machines. Longer term, the snitch could be used to manage end-to-end quality of service, Ranganathan said.