SAN JOSE, Calif. – A senior Google software engineer called for new techniques to clear clogs out of growing data center networks in a keynote at the annual Hot Interconnects event here. They could form a new app ripe for a silicon accelerator.
Nandita Dukkipati described traffic shaping software that’s slashing latencies while trimming CPU overheads for the search giant. One chip maker said it already has baked similar techniques into one of its Ethernet adapters at the request of Google’s rival Microsoft.
Today, many data centers manage traffic by creating queues to improve efficiency, but that approach is hitting a wall. Google described techniques using time-based isolation to prevent competing jobs from colliding.
“We should invest more in isolation techniques across the board in NICs, switches and hypervisors. We pay attention to efficiency, but not enough to isolation — we think of queues but let’s think of time,” Dukkipati told an audience of networking chip and systems engineers.
Queues eat up CPU time computing complex algorithms that use hefty data structures and require significant garbage collection. In addition, they are heavy users of memory and require synchronizing processes that can add as much as a second to latencies.
“Today’s servers can hold hundreds of virtual machines, generating 25,000 flows to isolate. The numbers of VMs and queues are growing, and it’s not sustainable,” she said.
Next page: Search giant’s code cuts latency, CPU overhead
Today's network traffic-shaping programs don't scale to the needs of big data centers, said Google. (Images: Hot Interconnects)