Can I do that AI thing on Dell PowerFlex?
The simple answer is Yes, you can do that AI thing with Dell PowerFlex. For those who might have been busy with other things, AI stands for Artificial Intelligence and is based on trained models that allow a computer to “think” in ways machines haven’t been able to do in the past. These trained models (neural networks) are essentially a long set of IF statements (layers) stacked on one another, and each IF has a ‘weight’. Once something has worked through a neural network, the weights provide a probability about the object. So, the AI system can be 95% sure that it’s looking at a bowl of soup or a major sporting event. That, at least, is my overly simplified description of how AI works. The term carries a lot of baggage as it’s been around for more than 70 years, and the definition has changed from time to time. (See The History of Artificial Intelligence.)
Most recently, AI has been made famous by large language models (LLMs) for conversational AI applications like ChatGPT. Though these applications have stoked fears that AI will take over the world and destroy humanity, that has yet to be seen. Computers still can do only what we humans tell them to do, even LLMs, and that means if something goes wrong, we their creators are ultimately to blame. (See ‘Godfather of AI’ leaves Google, warns of tech’s dangers.)
The reality is that most organizations aren’t building world destroying LLMs, they are building systems to ensure that every pizza made in their factory has exactly 12 slices of pepperoni evenly distributed on top of the pizza. Or maybe they are looking at loss prevention, or better traffic light timing, or they just want a better technical support phone menu. All of these are uses for AI and each one is constructed differently (they use different types of neural networks).
We won’t delve into these use cases in this blog because we need to start with the underlying infrastructure that makes all those ideas “AI possibilities.” We are going to start with the infrastructure and what many now consider a basic (by today’s standards) image classifier known as ResNet-50 v1.5. (See ResNet-50: The Basics and a Quick Tutorial.)
That’s also what the PowerFlex Solution Engineering team did in the validated design they recently published. This design details the use of ResNet-50 v1.5 in a VMware vSphere environment using NVIDIA AI Enterprise as part of PowerFlex environment. They started out with the basics of how a virtualized NVIDIA GPU works well in a PowerFlex environment. That’s what we’ll explore in this blog – getting started with AI workloads, and not how you build the next AI supercomputer (though you could do that with PowerFlex as well).
In this validated design, they use the NVIDIA A100 (PCIe) GPU and virtualized it in VMware vSphere as a virtual GPU or vGPU. With the infrastructure in place, they built Linux VMs that will contain the ResNet-50 v1.5 workload and vGPUs. Beyond just working with traditional vGPUs that many may be familiar with, they also worked with NVIDIA’s Multi-Instance GPU (MIG) technology.
NVIDIA’s MIG technology allows administrators to partition a GPU into a maximum of seven GPU instances. Being able to do this provides greater control of GPU resources, ensuring that large and small workloads get the appropriate amount of GPU resources they need without wasting any.
PowerFlex supports a large range of NVIDIA GPUs for workloads, from VDI (Virtual Desktops) to high end virtual compute workloads like AI. You can see this in the following diagram where there are solutions for “space constrained” and “edge” environments, all the way to GPUs used for large inferencing models. In the table below the diagram, you can see which GPUs are supported in each type of PowerFlex node. This provides a tremendous amount of flexibility depending on your workloads.
The validated design describes the steps to configure the architecture and provides detailed links to the NVIDIAand VMware documentation for configuring the vGPUs, and the licensing process for NVIDIA AI Enterprise.
These are key steps when building an AI environment. I know from my experience working with various organizations, and from teaching, that many are not used to working with vGPUs in Linux. This is slowly changing in the industry. If you haven’t spent a lot of time working with vGPUs in Linux, be sure to pay attention to the details provided in the guide. It is important and can make a big difference in your performance.
The following diagram shows the validated design’s logical architecture. At the top of the diagram, you can see four Ubuntu 22.04 Linux VMs with the NVIDIA vGPU driver loaded in them. They are running on PowerFlex hosts with VMware ESXi deployed. Each VM contains one NVIDIA A100 GPU configured for MIG operations. This configuration leverages a two-tier architecture where storage is provided by separate PowerFlex software defined storage (SDS) nodes.
A design like this allows for independent scalability for your workloads. What I mean by this is during the training phase of a model, significant storage may be required for the training data, but once the model clears validation and goes into production, storage requirements may be drastically different. With PowerFlex you have the flexibility to deliver the storage capacity and performance you need at each stage.
This brings us to testing the environment. Again, for this paper, the engineering team validated it using ResNet-50 v1.5 using the ImageNet 1K data set. For this validation they enabled several ResNet-50 v1.5 TensorFlow features. These include Multi-GPU training with Horovod, NVIDIA DALI, and Automatic Mixed Precision (AMP). These help to enable various capabilities in the ResNet-50 v1.5 model that are present in the environment. The paper then describes how to set up and configure ResNet-50 v1.5, the features mentioned above, and details about downloading the ImageNet data.
At this stage they were able to train the ResNet-50 v1.5 deployment. The first iteration of training used the NVIDIA A100-7-40C vGPU profile. They then repeated testing with the A100-4-20C vGPU profile and the A100-3-20C vGPU profile. You might be wondering about the A100-2-10C vGPU profile and the A100-1-5C profile. Although those vGPU profiles are available, they are more suited for inferencing, so they were not tested.
The results from validating the training workloads for each vGPU profile is shown in the following graph. The vGPUs were running near 98% capacity according to nvitop during each test. The CPU utilization was 14% and there was no bottle neck with the storage during the tests.
With the models trained, the guide then looks at how well inference runs on the MIG profiles. The following graph shows inferencing images per second of the various MIG profiles with ResNet-50 v1.5.
It’s worth noting that the last two columns show the inferencing running across multiple VMs, on the same ESXi host, that are leveraging MIG profiles. This also shows that GPU resources are partitioned with MIG and that resources can be precisely controlled, allowing multiple types of jobs to run on the same GPU without impacting other running jobs.
This opens the opportunity for organizations to align consumption of vGPU resources in virtual environments. Said a different way, it allows IT to provide “show back” of infrastructure usage in the organization. So if a department only needs an inferencing vGPU profile, that’s what they get, no more, no less.
It’s also worth noting that the results from the vGPU utilization were at 88% and CPU utilization was 11% during the inference testing.
These validations show that a Dell PowerFlex environment can support the foundational components of modern-day AI. It also shows the value of NVIDIA’s MIG technology to organizations of all sizes: allowing them to gain operational efficiencies in the data center and enable access to AI.
Which again answers the question of this blog, can I do that AI thing on Dell PowerFlex… Yes you can run that AI thing! If you would like to find out more about how to run your AI thing on PowerFlex, be sure to reach out to your Dell representative.
Resources
- The History of Artificial Intelligence
- ‘Godfather of AI’ leaves Google, warns of tech’s dangers
- ResNet-50: The Basics and a Quick Tutorial
- Dell Validated Design for Virtual GPU with VMware and NVIDIA on PowerFlex
- NVIDIA NGC Catalog ResNet v1.5 for PyTorch
- NVIDIA AI Enterprise
- NVIDIA A100 (PCIe) GPU
- NVIDIA Virtual GPU Software Documentation
- NVIDIA A100-7-40C vGPU profile
- NVIDIA Multi-Instance GPU (MIG)
- NVIDIA Multi-Instance GPU User Guide
- Horovod
- ImageNet
- DALI
- Automatic Mixed Precision (AMP)
- nvitop
Author: Tony Foster
Sr. Principal Technical Marketing Engineer
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Related Blog Posts
Accelerating Distributed Training in a Multinode Virtualized Environment
Fri, 13 May 2022 13:57:13 -0000
|Read Time: 0 minutes
Introduction
In the age of deep learning (DL), with complex models, it is vital to have a system that allows faster distributed training. Depending on the application, some DL models require more frequent retraining and fine-tuning of the hyperparameters to be deployed in the production environment. It is important to understand the best practices to improve multinode distributed training performance.
Networking is critical in a distributed training setup as there are numerous gradients exchanged between the nodes. The complexity increases as we increase the number of nodes. In the past, we have seen the benefits of using:
- Direct Memory Access (DMA), which enables a device to access host memory without the intervention of CPUs
- Remote Direct Memory Access (RDMA), which enables access to memory on a remote machine without interrupting the CPU processes on that system
This blog examines performance when direct communication is established between the GPUs in multinode training experiments run on Dell PowerEdge servers with NVIDIA GPUs and VMware vSphere.
GPUDirect RDMA
Introduced as part of Kepler class GPUs and CUDA 5.0, GPUDirect RDMA enables a direct communication path between NVIDIA GPUs and third-party devices such as network interfaces. By establishing direct communication between the GPUs, we can eliminate the critical bottleneck where data needs to be moved into the host system memory before it can be sent over the network, as shown in the following figure:
Figure 1: Direct Communication – GPUDirect RDMA
For more information, see:
System details
The following table provides the system details:
Table 1: System details
Component | Details |
Server | Dell PowerEdge R750xa (NVIDIA-Certified System) |
Processor | 2 x Intel Xeon Gold 6338 CPU @ 2.00 GHz |
GPU | 4 x NVIDIA A100 PCIe |
Network adapters | Mellanox ConnectX-6 Dual port 100 GbE and 25 GbE |
Storage | Dell PowerScale |
ESXi version | 7.0.3 |
BIOS version | 1.1.3 |
GPU driver version | 470.82.01 |
CUDA Version | 11.4 |
Setup
The setup for multinode training in a virtualized environment is outlined in our previous blog.
At a high level, after Address Translation Services (ATS) is enabled on VMware ESXi, the VMs, and ConnectX-6 NIC:
- Enable mapping between logical and physical ports.
- Create a Docker container with Mellanox OFED drivers, Open MPI Library, and NVIDIA-optimized TensorFlow.
- Set up a keyless SSH login between VMs
Performance evaluation
For evaluation, we use tf_cnn_benchmarks using the ResNet50 model and synthetic data with a local batch size of 1024. Each VM is configured with 32 vCPUs, 64 GB of memory, and one NVIDIA A100 PCIE 80 GB GPU. The experiments are performed by using a data parallelism approach in a distributed training setup, scaling up to four nodes. The results are based on averaging three experiment runs. Single-node experiments are only for comparison as there is no internode communication.
Note: Use the ibdev2netdev utility to display the installed Mellanox ConnectX-6 card along with the mapping of ports. In the following figures, ON and OFF indicate if the mapping is enabled between logical and physical ports.
The following figure shows performance when scaling up to four nodes using Mellanox ConnectX-6 Dual Port 100 GbE. It is clear that the throughput increases significantly when the mapping is enabled (ON), providing direct communication between NVIDIA GPUs. The two-node experiments show an improvement in throughput of 18.7 percent while the four node experiments improve throughput by 26.7 percent.
Figure 2: 100 GbE network performance
The following figure shows the scaling performance comparison between Mellanox ConnectX-6 Dual Port 100 GbE and Mellanox ConnectX-6 Dual Port 25 GbE while performing distributed training of the ResNet50 model. Using 100 GbE, two-node experiment results show an improved throughput of six percent while four-node experiments show an improved performance of 11.6 percent compared to 25 GbE.
Figure 3: 25 GbE compared to 100 GbE network performance
Conclusion
In this blog, we considered GPUDirect RDMA and a few required steps to setup multinode experiments in the virtualized environment. The results showed that scaling to a larger number of nodes boosts throughput significantly when establishing direct communication between GPUs in a distributed training setup. The blog also showcased the performance comparison between Mellanox ConnectX-6 Dual Port 100 GbE and 25 GbE network adapters used for distributed training of a ResNet50 model.
Comparison of Top Accelerators from Dell Technologies’ MLPerf™ Inference v3.0 Submission
Fri, 21 Apr 2023 21:43:39 -0000
|Read Time: 0 minutes
Abstract
Dell Technologies recently submitted results to MLPerfTM Inference v3.0 in the closed division. This blog highlights the NVIDIA H100 PCIe GPU and compares the results to the NVIDIA A100 PCIe GPU with the PCIe form factor held constant.
Introduction
MLPerf Inference v3.0 submission falls under the benchmarking pillar of the MLCommonsTM consortium with the objective to make fair comparisons across server configurations. Submissions that are made to the closed division warrant an equitable comparison of the systems.
This blog highlights the closed division submissions Dell Technologies made with the NVIDIA A100 GPU using the PCIe (peripheral component interconnect express) form factor. The PCIe form factor is an interfacing standard for connecting various high-speed components in hardware such as a computer or a server. Servers include a certain number of PCIe slots in which to insert GPUs or other additional cards. Note that there are different physical configurations for the slots to indicate the number of lanes for data to travel to and from the PCIe card. The NVIDIA H100 GPU is truly the latest and greatest GPU with NVIDIA AI Enterprise included; it is a dual-slot air cooled PCIe generation 5.0 GPU. This GPU runs at a memory bandwidth speed of over 2,000 megabits per second and up to seven Multi-Instance GPUs at 10 gigabytes each. The NVIDIA A100 80 GB GPU is a dual-slot PCIe generation 4.0 GPU that runs at a memory bandwidth speed of over 2,000 megabits per second.
NVIDIA H100 PCIe GPU and NVIDIA A100 PCIe GPU comparison
In addition to making a submission with the NVIDIA A100 GPU, Dell Technologies made a submission with the NVIDIA H100 GPU. To make a fair comparison, the systems were identical and the PCIe form factor was held constant.
Platform | Dell PowerEdge R750xa (4x A100-PCIe-80GB, TensorRT) | Dell PowerEdge R750xa (4x H100-PCIe-80GB, TensorRT) |
Round | V3.0 | |
MLPerf System ID | R750xa_A100_PCIe_80GBx4_TRT | R750xa_H100_PCIe_80GBx4_TRT |
Operating system | CentOS 8.2 | |
CPU | Intel Xeon Gold 6338 CPU @ 2.00 GHz | |
Memory | 1 TB | 1 TB |
GPU | NVIDIA A100-PCIe-80GB | NVIDIA H100-PCIe-80GB |
GPU form factor | PCIe | |
GPU memory configuration | HBM2e | |
GPU count | 4 | |
Software stack | TensorRT 8.6 CUDA 12.0 cuDNN 8.8.0 Driver 525.85.12 DALI 1.17.0 | TensorRT 8.6 CUDA 12.0 cuDNN 8.8.0 Driver 525.60.13 DALI 1.17.0 |
Table 1: Software stack of submissions made on NVIDIA A100 PCIe and NVIDIA H100 PCIe GPUs for MLPerf Inference v3.0 on the Dell PowerEdge R750xa server
In the following figure, the per card numbers are normalized over the NVIDIA A100 GPU results to show a readable comparison of the GPUs on the same system. Across object detection, medical image segmentation, and speech to text and natural language processing, the latest NVIDIA H100 GPU outperforms its predecessor in all categories. Note the outstanding performance of the Dell PowerEdge R750xa server with NVIDIA H100 GPUs with the BERT benchmark in the high accuracy mode. With the advancements in generative artificial intelligence, the Dell PowerEdge R750xa server is a versatile, reliable, and high performing platform.
Figure 1: Normalized per GPU comparison of NVIDIA A100 and NVIDIA H100 GPUs on the Dell PowerEdge R750xa server
The following figures show absolute numbers for a comparison of the NVIDIA H100 and NVIDIA A100 GPUs.
Figure 2: Per GPU comparison of NVIDIA A100 and NVIDIA H100 GPUs for RetinaNet on the PowerEdge R750xa server
Figure 3: Per GPU comparison of NVIDIA A100 and NVIDIA H100 GPUs for 3D-Unet on the PowerEdge R750xa server
Figure 4: Per GPU comparison of NVIDIA A100 and NVIDIA H100 GPUs for RNNT on the PowerEdge R750xa server
Figure 5: Per GPU comparison of NVIDIA A100 and NVIDIA H100 GPUs for BERT on the PowerEdge R750xa server
These results can be found on the MLCommons website.
Submissions made with the NVIDIA A100 PCIe GPU
In this round of submissions, Dell Technologies submitted results on the PowerEdge R750xa server packaged with four NVIDIA A100 80 GB PCIe GPUs. In previous rounds, the PowerEdge R750xa server showed outstanding performance across all the benchmarks. For a deeper dive of a previous round's submission, check out our blog from MLPerf Inference v2.0. From the previous round of MLPerf Inference v2.1 submissions, Dell Technologies submitted results on an identical system. However, across the two rounds of submissions, the main difference is the upgrades in the software stack, as described in the following table:
Platform | Dell PowerEdge R750xa (4x A100-PCIe-80GB, TensorRT) | Dell PowerEdge R750xa (4x A100-PCIe-80GB, TensorRT) |
Round | V3.0 | V2.1 |
MLPerf System ID | R750xa_A100_PCIe_80GBx4_TRT | |
Operating system | CentOS 8.2 | |
CPU | Intel Xeon Gold 6338 CPU @ 2.00 GHz | |
Memory | 512 GB | |
GPU | NVIDIA A100-PCIe-80GB | |
GPU form factor | PCIe | |
GPU memory configuration | HBM2e | |
GPU count | 4 | |
Software stack | TensorRT 8.6 CUDA 12.0 cuDNN 8.8.0 Driver 525.85.12 DALI 1.17.0 | TensorRT 8.4.2 CUDA 11.6 cuDNN 8.4.1 Driver 510.39.01 DALI 0.31.0 |
Table 2: Software stack for submissions made on the NVIDIA A100 PCIe GPU in MLPerf Inference v3.0 and v2.1
Comparison of PowerEdge R750xa NVIDIA A100 results from Inference v3.0 and v2.1
Object detection
The RetinaNet benchmark falls under the object detection category and uses the OpenImages dataset. The results from Inference v3.0 show a less than 0.05 percent difference in the Server scenario and a 21.53 percent difference in the Offline scenario. A potential reason for this result might be NVIDIA’s optimizations, as outlined in their technical blog.
Figure 6: RetinaNet Server and Offline results on the PowerEdge R750xa server from Inference v3.0 and Inference v2.1
Medical image segmentation
The 3D-Unet benchmark performs the KiTS 2019 kidney tumor segmentation task. Across the two rounds of submission, the PowerEdge R750xa server performed consistently well with a 0.3 percent difference in both the default and high accuracy modes.
Figure 7: 3D-UNet Offline results on the PowerEdge R750xa server from Inference v3.0 and v2.1
Speech to text
The Recurrent Neural Network Transducers (RNNT) model falls under the speech recognition category. This benchmark accepts raw audio samples and produces the corresponding character transcription. In the Server scenario, the results are within a 2.25 percent difference and 0.41 percent difference in the Offline scenario.
Figure 8: RNNT Server and Offline results on the Dell PowerEdge R750xa server from Inference v3.0 and v2.1
Natural language processing
Bidirectional Encoder Representation from Transformers (BERT) is a state-of-the-art language representational model for Natural Language Processing applications. This benchmark performs the SQuAD question answering task. The BERT benchmark consists of default and high accuracy modes for the Offline and Server scenarios. For the Server scenarios, the default mode results are within a 1.69 percent range and 3.12 percent range for the high accuracy mode. For the Offline scenarios, a similar behavior is noticeable in which the default mode results are within a 0.86 percent range and 3.65 percent range in the high accuracy mode.
Figure 9: BERT Server and Offline results on the PowerEdge R750xa server from Inference v3.0 and v2.1
Conclusion
Across the various rounds of submissions to the MLPerf Inference benchmark suite, the PowerEdge R750xa server has been a consistent top performer for any machine learning tasks ranging from object detection, medical image segmentation, speech to text and natural language processing. The PowerEdge R750xa server continues to be an excellent server choice for machine learning inference workloads. Customers can take advantage of the diverse results submitted on the Dell PowerEdge R750xa server with the NVIDIA H100 GPU to make an informed decision for their specific solution needs.