Configuring SBC SWe in OpenStack Cloud Environment for GPU Transcoding

Supported Deployment Scenarios

GPU acceleration is supported on SBC SWe I-SBC and T-SBC instances on OpenStack (Newton and above). T-SBC is a component in a Distributed SBC architecture that provides transcoding service.

GPU devices are attached to SBC cloud instances through PCIe pass-through – a single GPU device can be used by only one instance at a time. The process of enabling PCIe pass-through in OpenStack is detailed later in this document. For performance considerations, NUMA locality of devices should be ensured.

Supported GPU Devices

NVIDIA Tesla V100(PCIe)

Supported Codecs

The following codecs are supported:

• Codecs supported on both GPU and CPU: AMR-NB, AMR-WB, EVRC, EVRCB, G729, G722, EVS, OPUS 
• CPU only codecs :  G723, G726, G7221, ILBC, SILK_8, SILK_16, G7112G711, T38,G711

For more information on "GPU + CPU codecs", see the section Dynamic Codec Allocation.

Dynamic Codec Allocation

The SBC dynamically manages GPU and CPU transcoding resources so they respond to various codec combinations without impacting service. The SBC leverages both GPU and CPU transcoding resources to support an incoming codec request. If GPU resources are available, the SBC utilizes these GPU resources to support GPU-supported codecs. If GPU resources are not available, the SBC utilizes CPU resources (if available) to support GPU-supported codecs. The SBC utilizes CPU resources (if available) to support non-GPU supported codecs. For information about GPU- and CPU-supported codecs, refer to Supported Codecs.

The SBC NRM congestion monitoring mechanism monitors all UXPAD processes for congestion.

Best Practice

Ribbon recommends monitoring of the status of codec channel capacities for codecs provisioned on GPU (on a per GPU device basis), as well as on CPU.

GPU Transcode Status

Shows codec channel capacities on a per GPU device basis.

Command Syntax

show table system gpuTranscodeStatus

Command Parameters

gpuTranscodeStatus Descriptions:

CPU Transcode Status

The cpuTranscodeStatus captures the information on spilled over channels due to the exhaustion of GPU resources. GPU codecs appear on the CPU when the GPU resources are exhausted and cannot accommodate GPU-supported codec channels, so the codec channels spill onto the CPU.

Command Syntax

show table system cpuTranscodeStatus

Command Parameters

cpuTranscodeStatus Descriptions:

• System - Cpu Transcode Status
• System - Gpu Transcode Status

Instantiating GPU T-SBC on OpenStack Cloud

The T-SBC is instantiated using the help of a specific heat template.  The GPU T-SBC requires a special flavor that has appropriate directives to utilize GPU devices of the compute node available for PCIe pass-through.

T-SBC Heat Template

The T-SBC instance should be launched using the heatRgNoDhcp-TSBC-template.yaml template. This template shares all fields of an M-SBC template, and additionally has the following fields:

Host Changes on OpenStack for Enabling GPU Devices

This section describes the changes needed on the Controller node and the Compute node hosting GPU cards in order to enable instances to use GPU devices. While this section focuses purely on the GPU aspect, Ribbon recommends that you refer to broader OpenStack performance tuning recommendations covered in the following links:

• VNF Performance Tuning
• Pre-Instantiation Requirements of OpenStack

intel_iommu=on iommu=pt rdblacklist=nouveau

grub2-mkconfig -o /etc/grub2.cfg

blacklist nouveau

pci_alias={"vendor_id":"10de", "product_id":"1db4","device_type":"type-PCI", "name":"v100gpu"}

systemctl restart OpenStack-nova-api.service

Guideline for Creating Flavors for GPU T-SBC Instances

Open the dashboard and create a flavor with the following properties. Check with your Ribbon account team to determine the appropriate instance size for your traffic needs.

After creating the flavor, update its metadata with the following key values.

Configuring the SBC for Invoking T-SBC

Refer to the following pages for basic configuration steps for the S-SBC and M-SBC:

• S-SBC Cluster Configuration using SBC Configuration Manager
• M-SBC Cluster Configuration using SBC Configuration Manager
• Instantiating SBC SWe on OpenStack using Heat Templates

For enabling T-SBC, some additional configurations are required in S-SBC and M-SBC which are described in subsequent sections.

Configuring and Activating T-SBC Cluster

Steps for configuration of T-SBC is similar to M-SBC with the following exception: The IP interface group creation procedure should create private interface groups instead of public. There are no public interface groups for T-SBC.

Additional Configuration for S-SBC

A DSP cluster needs to be configured in the S-SBC configuration to refer to the T-SBC cluster that is to be used for transcoding. The following steps describe the procedure for creation of this cluster:

Additional Configuration for M-SBC

Configure the private IP interface group for relaying media packets to T-SBC using steps from the "Configure Private LIF Groups in M-SBC" section of Invoking MRF as a Transcoder for D-SBC.

Licensing

All pre-existing licensing related to transcoding apply to GPU codecs as well. There is no separate license for GPU functionality.