Next-Generation Graphics Acceleration for Digital Workplaces from Dell EMC and NVIDIA
Fri, 09 Dec 2022 13:58:56 -0000
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Originally published June 2019
For most organizations undergoing a digital transformation, maintaining a good user experience on virtual desktops—an essential component of digital workplaces—is a challenge. Users naturally compare their new virtual desktop experience to their previous physical endpoint experience. As the user experience continues to gain importance in digital workplaces (see this blog for more information), it is essential that virtualized environments keep pace with growing demands for user experience improvements.
This focus on the new user experience is being addressed by developers of modern-day operating systems and applications, who strive to meet the high expectations of their consumers. For example, the Windows 10 operating system, which plays a significant role in today's digital transformation initiatives, is more graphics-intensive than its predecessors. A study by Lakeside Software's SysTrack Community showed a 32 percent increase in graphics requirements when you move from Windows 7 to Windows 10. Microsoft Office applications (PowerPoint, Outlook, Excel, and so on), Skype for Business collaboration software, and all modern-day web browsers are designed to use more graphics acceleration in their newest releases.
Dell EMC Ready Solutions for VDI with NVIDIA Tesla T4 GPU
Dell EMC Ready Solutions for VDI, coupled with NVIDIA GRID Virtual PC (GRID vPC) and Virtual Apps (GRID vApps) software, provides comprehensive graphics acceleration solutions for your desktop virtualization workloads. The core of the NVIDIA GRID software is NVIDIA vGPU technology. This technology creates virtual GPUs, which enables sharing of the underlying GPU hardware among multiple users or virtual desktops running concurrently on a single host. This video compares the quality of a “CPU-only” VDI desktop with a VDI desktop powered by NVIDIA vGPU technology.
The latest NVIDIA GPU offering that supports virtualization is the NVIDIA Tesla T4, which is a universal GPU that can cater to a variety of workloads. The Tesla T4 comes with a 16 GB DDR6 memory. It operates at 70 W, providing higher energy efficiency and lower operating costs than its predecessors, and has a single-slot PCIe form factor. You can configure up to six Tesla T4s in a single Dell EMC PowerEdge R740xd server, providing the highest density for GPU-accelerated VMs in a Dell EMC server. For more details about the NVIDIA Tesla T4 GPU, see the Tesla T4 for Virtualization Technology Brief.
Image courtesy NVIDIA Corporation
Figure 1. NVIDIA vGPU technology stack
Tesla T4 vs. earlier Tesla GPU cards
Let's compare the NVIDIA Tesla T4 with other widely used cards—the NVIDIA Tesla P40 and the NVIDIA Tesla M10.
Tesla T4 vs. Tesla P40:
- The Tesla T4 comes with a maximum framebuffer of 16 GB. In a PowerEdge R740xd server, T4 cards can provide up to 96 GB of memory (16 GB x 6 GPUs), compared to the maximum 72 GB provided by the P40 cards (24 GB x 3 GPUs). So, for higher user densities and cost efficiency, the Tesla T4 is a better option in VDI workloads.
- You might have to sacrifice 3, 6, 12, and 24 GB profiles when using the T4, but 2 GB and 4 GB profiles, which are the most tested and configured profiles in VDI workloads, work well with the Tesla T4. However, NVIDIA Quadro vDWS use cases, which require higher memory per profile, are encouraged to use Tesla P40.
Tesla T4 vs. Tesla M10:
- In the PowerEdge R740xd server, three Tesla M10 cards can give you the same 96 GB memory as six Tesla T4 cards in a PowerEdge R740xd server. However, when it comes to power consumption, the six Tesla T4 cards consume only 420 W (70 W x 6 GPUs), while the three Tesla M10 GPUs consume 675 W (225 W x 3 GPUs), a substantial difference of 255 W per server. When compared to the Tesla M10, the Tesla T4 provides power savings, reducing your data center operating costs.
- Tesla M10 cards support a 512 MB profile, which is not supported by the Tesla T4. However, the 512 MB profile is not a viable option in today’s modern-day workplaces, where graphics-intensive Windows 10 operating systems, multi-monitors, and 4k monitors are prevalent.
The following table provides a summary of the Tesla T4, P40, and M10 cards.
Table 1. Comparison of NVIDIA Tesla T4, P40 & M10
GPU | Form factor | GPUs/board | Memory size | vGPU profiles | Power |
T4 | PCIe 3.0 single slot | 1 | 16 GB GDDR6 | 1 GB, 2 GB, 4 GB, 8 GB, 16 GB | 70 W |
P40 | PCIe 3.0 dual slot | 1 | 24 GB GDDR5 | 1 GB, 2 GB, 3 GB, 4 GB, 6 GB, 8 GB, 12 GB, 24 GB | 250 W |
M10 | PCIe 3.0 dual slot | 4 | 32 GB GDDR5 | .5 GB, 1 GB, 2 GB, 4 GB, 8 GB | 225 W |
(8 per GPU) |
GPU sizing and support for mixed workloads
With multi-monitors and 4K monitors becoming a norm in the modern workplace, streaming high-resolution videos can saturate the encoding engine on the GPUs and increase the load on the CPUs, affecting the performance and scalability of VDI systems. Thus, it is important to size the GPUs based on the number of encoding streams and required frames per second (fps). The Tesla T4 comes with an enhanced NVIDIA NVENC encoder that can provide higher compression and better image quality in H.264 and H.265 (HEVC) video codecs. The Tesla T4 can encode 22 streams at 720 progressive scan (p) resolution, with simultaneous display in high-quality mode. On average, the Tesla T4 can also handle 10 streams at 1080p and 2–3 streams at Ultra HD (2160p) resolutions. Running in a low-latency mode, it can encode 37 streams at 720p resolution, 17–18 streams at 1080p resolution, and 4–5 streams in Ultra HD.
VDI remote protocols such as VMware Blast Extreme can use NVIDIA GRID software and the Tesla T4 to encode video streams in H.265 and H.264 codecs, which can reduce the encoding latency and improve fps, providing a better user experience in digital workplaces. The new Tesla T4 NVENC encoder provides up to 25 percent bitrate savings for H.265 and up to 15 percent bitrate savings for H.264. Refer to this NVIDIA blog to learn more about the Tesla T4 NVENC encoding improvements.
The Tesla T4 is well suited for use in a data center with mixed workloads. For example, it can run VDI workloads during the day and compute workloads at night. This concept, known as VDI by Day, HPC by Night, increases the productivity and utilization of data center resources and reduces data center operating costs.
Tesla T4 testing on Dell EMC VDI Ready Solution
At Dell EMC, our engineering team tested the NVIDIA Tesla T4 on our Ready Solutions VDI stack based on the Dell EMC VxRail hyperconverged infrastructure. The test bed environment was a 3-node VxRail V570F appliance cluster that was optimized for VDI workloads. The cluster was configured with 2nd Generation Intel Xeon Scalable processors (Cascade Lake) and with NVIDIA Tesla T4 cards in one of the compute hosts. The environment included the following components:
- PowerEdge R740xd server
- Intel Xeon Gold 6248, 2 x 20-core, 2.5 GHz processors (Cascade Lake)
- NVIDIA Tesla T4 GPUs with 768 GB memory (12 x 64 GB @ 2,933 MHz)
- VMware vSAN hybrid datastore using an SSD caching tier
- VMware ESXi 6.7 hypervisor
- VMware Horizon 7.7 VDI software layer
Dell EMC Engineering used the Power Worker workload from Login VSI for testing. You can find background information about Login VSI analysis at Login VSI Analyzing Results.
The GPU-enabled PowerEdge compute server hosted 96 VMs with a GRID vPC vGPU profile (T4-1B) of 1 GB memory each. The host was configured with six NVIDIA Tesla T4 cards, the maximum possible configuration for the NVIDIA Tesla T4 in a Dell PowerEdge R740xd server.
With all VMs powered on, the host server recorded a steady-state average CPU utilization of approximately 95 percent and a steady-state average GPU utilization of approximately 34 percent. Login VSImax—the active number of sessions at the saturation point of the system—was not reached, which means the performance of the system was very good. Our standard threshold of 85 percent for average CPU utilization was relaxed for this testing to demonstrate the performance when graphics resources are fully utilized (96 profiles per host). You might get a better user experience with managing CPU at a threshold of 85 percent by decreasing user density or by using a higher-binned CPU. However, if your CPU is a previous generation Intel Xeon Scalable processor (Skylake), the recommendation is to use only up to four NVIDIA Tesla cards per PowerEdge R740xd server. With six T4 cards per PowerEdge R740xd server, the GPUs were connected to both x8 and x16 lanes. We found no issues using both x8 and x16 lanes and, as indicated by the Login VSI test results, system performance was very good.
Dell EMC Engineering performed similar tests with a Login VSI Multimedia Workload using 48 vGPU-enabled VMs on a GPU-enabled compute host, each having a Quadro vDWS-vGPU profile (T4-2Q) with a 2 GB frame buffer. With all VMs powered on, the average steady-state CPU utilization was approximately 48 percent, and the average steady-state GPU utilization was approximately 35 percent. The system performed well and the user experience was very good.
For more information about the test-bed environment configuration and additional resource utilization metrics, see the design and validation guides for VMware Horizon on VxRail and vSAN on our VDI Info Hub.
Summary
Just as Windows 10 and modern applications are incorporating more graphics to meet user expectations, virtualized environments must keep pace with demands for an improved user experience. Dell EMC Ready Solutions for VDI, coupled with the NVIDIA Tesla T4 vGPU, are tested and validated solutions that provide the high-quality user experience that today’s workforce demands. Dell EMC Engineering used Login VSI’s Power Worker Workload and Multimedia Workload to test Ready Solutions for VDI with the Tesla T4, and observed very good results in both system performance and user experience.
In the next blog, we will discuss the affect of memory speed on VDI user density based on testing done by Dell EMC VDI engineering team. Stay tuned and we’d love to get your feedback!