Introduction

MLPerf (https://mlperf.org) Inference is a benchmark suite for measuring how fast Machine Learning (ML) and Deep Learning (DL) systems can process input inference data and produce results using a trained model. The benchmarks belong to a diversified set of ML use cases that are popular in the industry and provide a standard for hardware platforms to perform ML-specific tasks. Hence, good performance under these benchmarks signifies a hardware setup that is well optimized for real world ML inferencing use cases.

System under Test (SUT)

• Server – Dell EMC PowerEdge R740
• GPU – NVIDIA Tesla T4
• Framework – TensorRT™ 7.2.0.14

Dell EMC PowerEdge R740

Table 1   Dell EMC PowerEdge R740 technical specifications

NVIDIA Tesla T4

The NVIDIA Tesla T4, based on NVIDIA’s Turing architecture is one of the most widely used AI inference accelerators. The Tesla T4 features NVIDIA Turing Tensor cores which enable it to accelerate all types of neural networks for images, speech, translation, and recommender systems, to name a few. Tesla T4 supports a wide variety of precisions and accelerates all major DL & ML frameworks, including TensorFlow, PyTorch, MXNet, Chainer, and Caffe2.

Table 2   NVIDIA Tesla T4 technical specifications

MLPerf Inference v0.7

The MLPerf inference benchmark measures how fast a system can perform ML inference using a trained model with new data that is provided in various deployment scenarios. Table 3 shows seven mature models that are in the official v0.7 release. 

Table 3   MLPerf Inference Suite v0.7

 The above models serve in various critical inference applications or use cases that are known as “scenarios.” Each scenario requires different metrics and demonstrates performance in a production environment. MLPerf Inference consists of four evaluation scenarios that are shown in Table 4:

• Single-stream
• Multi-stream
• Server
• Offline

Table 4   Deployment scenarios

Results

The units on which Inference is measured are based on samples and queries. A sample is a unit on which inference is run, such as an image or sentence. A query is a set of samples that are issued to an inference system together. For detailed explanation of definitions, rules and constraints of MLPerf Inference see: https://github.com/mlperf/inference_policies/blob/master/inference_rules.adoc#constraints-for-the-closed-division

Default Accuracy refers to a configuration where the model infers samples with at least 99% accuracy. High Accuracy refers to a configuration where the model infers samples with 99.9% accuracy. For MLPerf Inference v0.7 result submissions, Dell EMC used Offline and Server scenarios as they are more representative of datacenter systems. Offline scenario represents use cases where inference is done as a batch job (for instance using AI for photo sorting), while server scenario represents an interactive inference operation (translation app).

MLPerf Inference results on the PowerEdge R740

Table 5   PowerEdge R740 inference results

Table 5 above shows the raw performance of the R740_T4x4 SUT in samples/s for the offline scenario and queries for the server scenario. Detailed results for this and other configurations can be found at https://mlperf.org/inference-results-0-7/.

Figures 1 and 2 below show the raw data inference performance of the R740_T4x4 SUT for five of the six MLPerf benchmarks that were submitted. Each bar graph indicates the relative performance of inference operations that are completed in a set amount of time while bounded by latency constraints. The higher the bar graph is, the higher the inference capability of the platform. Figure 3 compares offline scenario performance to server scenario and figure 4 compares offline performance using the default and high accuracy. 

Figure 1   Default accuracy performance for (BERT,RNNT and SSD) offline and server scenarios

Figure 2   Default accuracy performance for DLRM and ResNet50 offline and server scenarios 

Figure 3   Comparing offline to server scenario performance   

Figure 4   Comparing offline default accuracy to high accuracy performance    

Figure 5   Comparing NVIDIA Tesla T4 configurations’ offline performance using R740_T4x4 as a baseline

Figure 5 shows the relative offline performance per GPU card for Tesla T4 configurations from several submitter organizations. 

 Figure 6   Relative cost of GPU card configurations using R740_T4x4 as baseline and its BERT default Performance

Figure 6 shows the relative price of each GPU configuration using the cost of Tesla T4 as the baseline and the corresponding price performance. The price/performance shown is an estimate to illustrate the “bang“ for the money that is spent on the GPU configurations and should not be taken as the price/performance of the entire SUT. In this case, the shorter the bar the better.

Key takeaways from the results

1. The R740_T4x4 configuration could successfully perform Inference operations using six different MLPerf benchmarks for the offline scenario and five for the offline scenario. 
2. Performance is relatively stable across the two datacenter-centric scenarios. Figure 3 shows that the R740_T4x4 inference performance scores for the offline and server scenarios across five different benchmarks are very close. This means that performance will not drastically change due to changes in the type of input stream. 
3. It is all about accelerators. Figure 5 shows that the relative performance per GPU card of several Tesla T4 configurations is within 4% of each other. These are SUTs with different server platforms from several submitter organizations. 4% is statistically insignificant as it could be attributed to the performance noise level of these systems.  
4. The more expensive GPUs provide better price/performance. From figure 6, the cost of the R7525_A100x3 configuration is 3x the cost of the reference configuration R740_T4x4 but its relative price/performance is 0.61x.
5. The price of the RTX8000 is 2.22x of the price of the Tesla T4 as searched from the Dell website. The RTX8000 can be used with fewer GPU cards, three compared to 8xT4, at a lower cost. From Figure 6, the R7525_RTX8000x3 is 0.8333 x the cost of the R7525_T4x8, and it posts better price/performance.
6. Generally, Dell Technologies provides server configurations with the flexibility to deploy customer inference workloads on systems that match their requirements.
   1. The NVIDIA T4 is a low profile, lower power GPU option that is widely deployed for inference due to its superior power efficiency and economic value.
   2. With 48 GB of GDDR6 memory, the NVIDIA Quadro RTX 8000 is designed to work with memory intensive workloads like creating the most complex models, building massive architectural datasets and visualizing immense data science workloads. Dell is the only vendor that submitted results using NVIDIA Quadro RTX GPUs.
   3. NVIDIA A100-PCIe-40G is a powerful platform that is popularly used for training state-of-the-art Deep Learning models. For customers who are not on a budget and have heavy Inference computational requirements, its initial high cost is more than offset by the better price/performance.

Conclusion

As shown in the charts above, Dell EMC PowerEdge R740 performed well in a wide range of benchmark scenarios. The benchmarks that are discussed in this blog included diverse use cases. For instance, image dataset inferencing (Object Detection using SSD-Resnet34 model on COCO dataset), language processing (BERT model used on SQUAD v1.1 for machine comprehension of texts), and recommendation engine (DLRM model with Criteo 1 TB clicks dataset).

The Dell EMC PowerEdge R7525 server provides exceptional MLPerf Inference v0.7 Results, which indicate that:

• Dell Technologies holds the #1 spot in performance per GPU with the NVIDIA A100-PCIe GPU on the DLRM-99 Server scenario
• Dell Technologies holds the #1 spot in performance per GPU with the NVIDIA A100-PCIe on the DLRM-99.9 Server scenario
• Dell Technologies holds the #1 spot in performance per GPU with the NVIDIA A100-PCIe on the ResNet-50 Server scenario

Summary

In this blog, we provide the performance numbers of our recently released Dell EMC PowerEdge R7525 server with two NVIDIA A100 GPUs on all the results of the MLPerf Inference v0.7 benchmark. Our results indicate that the PowerEdge R7525 server is an excellent choice for inference workloads. It delivers optimal performance for different tasks that are in the MLPerf Inference v0.7 benchmark. These tasks include image classification, object detection, medical image segmentation, speech to text, language processing, and recommendation. 

The PowerEdge R7525 server is a two-socket, 2U rack server that is designed to run workloads using flexible I/O and network configurations. The PowerEdge R7525 server features the 2nd Gen AMD EPYC processor, supports up to 32 DIMMs, has PCI Express (PCIe) Gen 4.0-enabled expansion slots, and provides a choice of network interface technologies to cover networking options. 

The following figure shows the front view of the PowerEdge R7525 server:

Figure 1. Dell EMC PowerEdge R7525 server

The PowerEdge R7525 server is designed to handle demanding workloads and for AI applications such as AI training for different kinds of models and inference for different deployment scenarios. The PowerEdge R7525 server supports various accelerators such as NVIDIA T4, NVIDIA V100S, NVIDIA RTX, and NVIDIA A100 GPU s. The following sections compare the performance of NVIDIA A100 GPUs with NVIDIA T4 and NVIDIA RTX GPUs using MLPerf Inference v0.7 as a benchmark.

The following table provides details of the PowerEdge R7525 server configuration and software environment for MLPerf Inference v0.7:

For more information about how to run the benchmark, see Running the MLPerf Inference v0.7 Benchmark on Dell EMC Systems.

MLPerf Inference v0.7 performance results

The MLPerf inference benchmark measures how fast a system can perform machine learning (ML) inference using a trained model in various deployment scenarios. The following results represent the Offline and Server scenarios of the MLPerf Inference benchmark. For more information about different scenarios, models, datasets, accuracy targets, and latency constraints in MLPerf Inference v0.7, see Deep Learning Performance with MLPerf Inference v0.7 Benchmark.

In the MLPerf inference evaluation framework, the LoadGen load generator sends inference queries to the system under test, in our case, the PowerEdge R7525 server with various GPU configurations. The system under test uses a backend (for example, TensorRT, TensorFlow, or PyTorch) to perform inferencing and sends the results back to LoadGen.

MLPerf has identified four different scenarios that enable representative testing of a wide variety of inference platforms and use cases. In this blog, we discuss the Offline and Server scenario performance. The main differences between these scenarios are based on how the queries are sent and received:

• Offline—One query with all samples is sent to the system under test. The system under test can send the results back once or multiple times in any order. The performance metric is samples per second.
• Server—Queries are sent to the system under test following a Poisson distribution (to model real-world random events). One query has one sample. The performance metric is queries per second (QPS) within latency bound.

Note:  Both the performance metrics for Offline and Server scenario represent the throughput of the system. 

In all the benchmarks, two NVIDIA A100 GPUs outperform eight NVIDIA T4 GPUs and three NVIDIA RTX800 GPUs for the following models:

• ResNet-50 image classification model
• SSD-ResNet34 object detection model
• RNN-T speech recognition model
• BERT language processing model
• DLRM recommender model
• 3D U-Net medical image segmentation model

The following graphs show PowerEdge R7525 server performance with two NVIDIA A100 GPUs, eight NVIDIA T4 GPUs, and three NVIDIA RTX8000 GPUs with 99% accuracy target benchmarks and 99.9% accuracy targets for applicable benchmarks:

• 99% accuracy (default accuracy) target benchmarks: ResNet-50, SSD-Resnet34, and RNN-T
• 99% and 99.9% accuracy (high accuracy) target benchmarks: DLRM, BERT, and 3D-Unet

99% accuracy target benchmarks

ResNet-50

The following figure shows results for the ResNet-50 model:

Figure 2. ResNet-50 Offline and Server inference performance

From the graph, we can derive the per GPU values. We divide the system throughput (containing all the GPUs) by the number of GPUs to get the Per GPU results as they are linearly scaled. 

SSD-Resnet34

The following figure shows the results for the SSD-Resnet34 model:

Figure 3. SSD-Resnet34 Offline and Server inference performance

RNN-T

The following figure shows the results for the RNN-T model:

Figure 4. RNN-T Offline and Server inference performance

99.9% accuracy target benchmarks

DLRM

The following figures show the results for the DLRM model with 99% and 99.9% accuracy:

Figure 5. DLRM Offline and Server Scenario inference performance – 99% and 99.9% accuracy                                   

 For the DLRM recommender and 3D U-Net medical image segmentation (see Figure 7) models, both 99% and 99.9% accuracy have the same throughput. The 99.9% accuracy benchmark also satisfies the required accuracy constraints with the same throughput as that of 99%.

BERT

The following figures show the results for the BERT model with 99%  and 99.9% accuracy:

Figure 6. BERT Offline and Server inference performance – 99% and 99.9% accuracy 

For the BERT language processing model, two NVIDIA A100 GPUs outperform eight NVIDIA T4 GPUs and three NVIDIA RTX8000 GPUs. However, the performance of three NVIDIA RTX8000 GPUs is a little better than that of eight NVIDIA T4 GPUs.

3D U-Net

For the 3D-Unet medical image segmentation model, only the Offline scenario benchmark is available.

The following figure shows the results for the 3D U-Net model Offline scenario:

Figure 7. 3D U-Net Offline inference performance 

For the 3D-Unet medical image segmentation model, since there is only offline scenario benchmark for 3D-Unet the above graph represents only Offline scenario.

The following table compares the throughput between two NVIDIA A100 GPUs, eight NVIDIA T4 GPUs, and three NVIDIA RTX8000 GPUs with 99% accuracy target benchmarks and 99.9% accuracy targets:

Conclusion

With support of NVIDIA A100, NVIDIA T4, or NVIDIA RTX8000 GPUs, Dell EMC PowerEdge R7525 server is an exceptional choice for various workloads that involve deep learning inference. However, the higher throughput that we observed with NVIDIA A100 GPUs translates to performance gains and faster business value for inference applications. 

Dell EMC PowerEdge R7525 server with two NVIDIA A100 GPUs delivers optimal performance for various inference workloads, whether it is in a batch inference setting such as Offline scenario or Online inference setting such as Server scenario. 

Next steps

In future blogs, we will discuss sizing the system (server and GPU configurations) correctly based on the type of workload (area and task).