CUPERTINO, Calif. — Next year, Microsoft will start plugging Altera FPGA cards into new servers it deploys to run its Bing search service. Someday it might make such cards a standard part of the million servers in its datacenters.
That's the goal for Andrew Putnam, part of a Microsoft Research that led to the current use of FPGAs for Bing. It talks at the annual Hot Chips event here Putnam and an engineer from China's search giant Baidu described their parallel efforts.
FPGAs are not a natural fit for cost-sensitive datacenters, but it turns out they make sense. "We started out focusing on Bing which needed help because it was not fast enough, not that we wanted to get FPGAs in the datacenter — we looked at software, then GPUs and then FPGAs," said Putnam in an interview with EE Times.
Putnam's team would up building a 10x10 cm card using a Stratix V FPGA with 8 GBytes memory. It slots into the standard server Microsoft's datacenter uses, drawing 25W from its PCI Express Gen 3 slot.
The Catapult board with an Altera Stratix V will help run Microsoft Bing in 2015.
The team also created special cabling to create a 6x8 Torus network to link all the FPGAs in a rack. It enables services run across multiple FPGAs and accessed without going through host server CPUs and their network.
In a pilot using 1,632 servers, the approach doubled throughput for Bing while adding less than 30% of the cost of the server. "That means we could use half the number of servers to do Bing," said Putnam, a huge savings for cost-sensitive datacenters.
That paved the way for use of the Catapult cards in Microsoft's new production servers running Bing, starting next year. "Retrofitting existing servers is really difficult and that's true of FPGAs or whatever," he said, noting the effort and risk of changing such massive underlying hardware.
The FPGAs accelerate the ranking of search terms, a new partition of the overall search job. "Bing and its 30,000 lines of gnarly code wasn't a natural fit for FPGAs," but his team has found other more natural Microsoft datacenter apps for its cards.
Next page: Putting more P into FPGAs
Andrew Putnam from Microsoft Research shows the Catapult board and the Microsoft server it plugs into.