Connectivity
The DPU dilemma: life beyond SmartNICs There’s a major shift happening in server hardware, and it’s emerged from a surprising direction: the humble network card
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e are near the start of the next major architectural shift in IT infrastructure,” says Paul Turner, vice president, product management vSphere at VMware in a blog. He’s talking about new servers which are built with maximum programmability in a single cost-effective form factor. And what made this revolution possible is a simple thing: making network cards smarter. The process began with the Smart network interface card or SmartNIC - and has led to a specialized chip: the DPU or data processing unit - an ambiguouslynamed device with a wide range of applications. “As these DPUs become more common we can expect to see functions like encryption/decryption, firewalling, packet inspection, routing, storage networking and more being handled by the DPU,” predicts Turner. The birth of SmartNICs Specialized chips exist because x86 family processors are great at general purpose tasks, but for specific jobs, they can be much slower than a purpose-built system. That’s why graphics processor chips (GPUs) have boomed, first in games consoles, then in AI systems. “The GPU was really designed to
be the best at doing the math to draw triangles,” explains Eric Hayes, CEO of Fungible, one of the leading exponents of the new network chips. “Jensen Huang at Nvidia was brilliant enough to apply that technology to machine learning, and realize that architecture is very well suited to that type of workload.” Like GPUs, SmartNICs began with a small job: offloading some network functions from the CPU, so network traffic could flow faster. And, like GPUs, they’ve eventually found themselves with a wide portfolio of uses. But the SmartNIC is not a uniform, one-size-fits-all category. They started to appear as networks got faster, and had to carry more users’ traffic, explains Baron Fung, an analyst at Delloro Group. “10Gbps is now more of a legacy technology,” Fung explained, in a DCD webinar. “Over the last few years we've seen general cloud providers shift towards 25 Gig, many of them are today undergoing the transition to 400 Gig.” At the same time, “cloud providers need
Peter Judge Global Editor
to consolidate workloads from thousands and thousands of end users. SmartNICs became one of the solutions to manage all that data traffic." Servers can get by with standard or “foundational” NICs up to around 200Gbps, says Fung. “Today, most of the servers in the market have standard NICs.” Above that, network vendors have created “performance” NICs, using specialized ASICs to offload network functions, but SmartNICs are different. “SmartNICs add another layer of performance over Performance NICs,“ says Fung. “Essentially, these devices boil down to being fully programmable devices with their own processor, operating system, integrated memory and network fabric. It’s like a server within a server, offering a different range of offload services from the host CPU.” It’s a growth area: “SmartNICs are relatively small in numbers now, but in the next few years, we see increasing adoption of these devices.” SmartNICS are moving from a specialist
“Over the last few years we've seen general cloud providers shift towards 25 Gig, many of them are today undergoing the transition to 400 Gig” Issue 43 • December 2021 / January 2022 61
