Researchers at HP, chipmaker ARM, and Facebook have dreamt up a new breed of server processor specifically designed to provide quick and efficient access to information on the web's most popular services.

In a paper due to be published next month, the researchers propose a chip that's custom-built to run Memcached, a popular open source software platform that lets services like Facebook, Twitter, and Wikipedia speed the delivery of data to the world's web surfers. In building this chip, you would start with a low-power processor not unlike the one in your cell phone, but then you would add hardware that could help Memcached zip information across a data center network.

It's an intriguing design, but more importantly, it provides a glimpse into how server chips are likely to change over the coming years – and how this will effect the competitive landscape among chipmakers. Today, Intel owns this market because it makes inexpensive general-purpose processors that run extremely fast. ARM's chips aren't as powerful, but the company has something else going for it. ARM licenses its designs to a wide range of chip makers who can then modify them and build all sorts of specialized gear – gear like the system-on-chip proposed in this new paper.

"We've already seen it in the cellphone world. With the iPhone, fifty percent of the chip area is accelerators specifically for this, that, and the other thing," says Thomas Wenisch, a computer science professor at the University of Michigan who also worked on the paper. "Cellphones and data centers are going to become more and more similar."

Intel knows this as well as anyone. Though it doesn't foster a ARM-like community of outside chip designers, it's already working to customize chips on behalf of companies like Facebook and Google, and like ARM, it's fashioning ultra-low-power chips suited to servers. But ARM provides the prospect of even greater specialization and choice – and that's what web outfits like Facebook are looking for.

With specialized chips, Facebook and other web giants can significantly reduce the power and cost need to operate their already massive networks of data centers. "Custom accelerators are just more energy efficient than general purpose processors," says Wenisch. "You'll see a general trend towards specialization."

The new research paper doesn't necessarily reveal the immediate plans of HP, ARM, or Facebook. HP declined to comment on the paper. ARM didn't respond to a request for comment. And Facebook says the paper was not an official company project. The Facebook researcher cited in the paper, David Meisner, did most of the work while completing his PhD thesis under Wenisch.

>'We've already seen it in the cellphone world. With the iPhone, fifty percent of the chip area is accelerators specifically for this, that, and the other thing. Cellphones and data centers are going to become more and more similar.' Thomas Wenisch

The paper also names two other former students of Wenisch: Kevin Lim, now with HP Labs, and Ali Saidi, now with ARM. The fifth name on the paper is HP Fellow Parthasarathy Ranganathan, a key figure behind Project Moonshot, the company's much-discussed effort to build servers from "cellphone-class" chips. But that doesn't mean HP will offer servers equipped with chips custom-built for Memcached.

What the paper shows is that there better ways of running certain software inside the vast data centers that underpin services such as Facebook, Amazon, and Twitter. About a year ago, Thomas Wenisch and his fellow researchers started testing Memcached on two different types of servers: one equipped with Intel's Xeon processor, a classic server chip, and one based on an Intel Atom, a chip originally built for cellphones. What they found is that neither was well suited to running Memcached. The Xeon was overkill, and the Atom just wasn't fast enough.

"Xeon class chips are good at this – but they're expensive and they consume a lot of energy," Wenisch says. "But, at least right now, chips like Atom can't run through the operating system code needed to put a packet across the network as fast as they need to."

At a place like Twitter, Memcached is used to store site data that's accessed more often than most. It stores this data not on hard drives, but in computer memory, so that that it can be accessed all the quicker. According to Wenisch, retrieving this data doesn't require much processing power. "It's a really a simple thing," he say. "There's a key in memory. You find it. And you ship it out over the network."

When they started the project, the researchers assumed that the Intel Atom would be well suited to this task. But as it turns out, the chip didn't have the juice needed for the final step. "We were expecting that it would be really great for this – much more cost effective, much more energy effective," he says. "But as it turns out, it's not so great. You still have to go through all this code to push a packet out onto the network – and that limits the performance. The lower-end processors just can't run the networking stack fast enough to really push the network to its limit."

The solution is to build a new chip that includes hardware whose sole purpose is to send the data over a network. Using tools developed by HP, the team mocked up a prototype of the chip, and using simulated models, they showed how effective this setup could be. They call this new architecture "Thin Servers with Smart Pipes," or TSSP for short.

Today, says Andy Konwinski, a University of California, at Berkeley researcher who builds software for use inside large data centers, most of this software still runs on standard server chips. But what this new research paper shows is standard chips aren't necessarily the way to go – something we've already heard from others, including Frank Frankovsky, who oversees hardware design at Facebook.

This is why Frankovsky and others are pleased that so many different chip makers are now building server processors based on ARM's low-power chip architecture and other designs. ARM licenses its core designs to outside companies like Applied Micro and Texas-startup Calxeda, who then modify it for particular tasks. In the end, this gives web giants like Facebook more options to choose from.

ARM chips are dominant in the world of cellphones, and many believe they've got a real shot at taking off in the web data center. "It's essentially a revolution," says Jason Mars, a professor at University of California, San Diego, who looks at ways of reducing power and cost in the data center. "This business model has taken the mobile market by storm," he says, "and it looks like it can translate to data centers."