What is RDMA and RoCE? SmartNICs explained.

Summary

As data applications grow in size and complexity, the need for high-speed storage and compute connections intensifies. The traditional NIC (Network Interface Card) has evolved with offloading technologies like RDMA (Remote Direct Memory Access), which enhances throughput and reduces latency by bypassing the CPU and OS. RDMA over Converged Ethernet (RoCE) allows Ethernet infrastructure to support these capabilities, offering high performance similar to InfiniBand. Additionally, Data Processing Units (DPUs) are emerging, embedding GPUs alongside NICs to further improve data transfer efficiency and parallel computing, optimizing workflows for demanding applications like AI, big data analytics, and deep learning.

Takeaways

• 😀 The increasing complexity and size of data sets put pressure on enterprise storage and compute power.
• 😀 Network interface cards (NICs) are responsible for connecting external storage to CPU and GPU compute resources within a server.
• 😀 NICs traditionally governed the speed of data transfer, but the CPU, operating system (OS), and system memory also contributed to processing and latency.
• 😀 To handle speeds above 10 gigabits per second, the concept of network card offloading was developed, where processing is offloaded to the NIC, bypassing the CPU, OS, and memory.
• 😀 RDMA (Remote Direct Memory Access) allows direct access to memory between computers without involving the OS, improving throughput and reducing latency.
• 😀 RDMA is particularly beneficial for high-performance computing tasks like AI, big data analytics, deep learning, and advanced visualization.
• 😀 RDMA was originally developed for Infiniband NICs, which offered higher bandwidth speeds than traditional Ethernet.
• 😀 Recent developments have allowed Ethernet to match Infiniband speeds through RDMA over Converged Ethernet (RoCE), preserving offloading capabilities while using Ethernet protocols.
• 😀 RoCE encapsulates Infiniband transport packets over Ethernet, enabling high bandwidth and low latency networking without replacing networking infrastructure.
• 😀 Some NICs now incorporate GPUs and Data Processing Units (DPUs) to facilitate data transfer and parallel computing, further reducing latency and bottlenecks for demanding workloads.

Q & A

What challenges arise as applications grow in functionality and data sets increase in size?

As applications become more complex and data sets grow, the connection between enterprise storage and compute resources faces increasing pressure, particularly in terms of bandwidth and throughput.

How does the connection between external storage and compute resources function within a server?

The connection is managed by the network interface card (NIC), which governs the data transfer speed between the server and external storage.

What was the role of the CPU, operating system, and system memory in the traditional NIC model?

In the traditional NIC model, the CPU, operating system, and system memory were responsible for determining the processing required for data transfers, introducing latency due to the extra stages involved.

What is RDMA, and how does it improve data transfer performance?

Remote Direct Memory Access (RDMA) allows direct access from one computer's memory to another's, bypassing the operating system. This reduces latency and increases throughput, particularly useful in high-performance computing tasks.

Why was RDMA initially developed for InfiniBand NICs?

RDMA was developed for InfiniBand NICs because InfiniBand offered higher bandwidth speeds than traditional Ethernet, making it ideal for high-performance computing applications.

What is Rocky, and how does it compare to InfiniBand?

Rocky stands for RDMA over Converged Ethernet and allows the same offloading capabilities as InfiniBand while using Ethernet protocols. It offers the benefits of InfiniBand (high bandwidth and low latency) without requiring a full infrastructure change.

How does Rocky encapsulate data for transfer?

Rocky encapsulates an InfiniBand transport packet over a physical Ethernet connection, enabling the high-speed, low-latency benefits of InfiniBand over standard Ethernet.

What are DPUs, and how do they help in data transfer and parallel compute tasks?

Data Processing Units (DPUs) are specialized NICs that include a GPU alongside the processing unit to handle data transfer and parallel compute tasks. This reduces latency and bottlenecks by offloading processing tasks from the CPU and memory.

What benefits do DPUs provide for demanding workflows and applications?

DPUs help reduce latency and bottlenecks by managing data transfer and compute processes directly on the NIC, allowing for more efficient execution of demanding workflows such as AI and deep learning applications.

What additional resources are available to learn more about NICs, Smart NICs, and DPUs?

The video offers a dedicated explanation about the differences between NICs, Smart NICs, and DPUs. Viewers are encouraged to subscribe to the channel and check out this additional content.