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Supported Deployment Scenarios

GPU acceleration is supported on SBC SWe cloud-based 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.

NVIDIA GRID is not supported.

Supported GPU Devices

NVIDIA Tesla V100(PCIe)

Supported Codecs

  • AMR-NB
  • G729
  • G722
  •  AMR-WB

Note

G.722 Silence Suppression is not supported with GPU transcoding.

Prerequisite Note

 The following procedures assume that the supported GPU devices have been properly installed on the server.

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:

Table : T-SBC Heat Template

Field

Description

Example or
Recommendation

gpu

Indicate whether to use GPU or CPU for transcoding. Should be set as true for GPU TSBCs.

Note: For GPU T-SBCs ,additional provisioning of codec percentages are required at the time of instantiation.

Transcode resources for codecs are reserved and fixed for the lifetime of the instance.

True

AMR

Percentage of channels to be allocated for AMR codec (0-100)

Applicable only when gpu field is True.

100

AMRWB

Percentage of channels to be allocated for AMRWB codec (0-100)

Applicable only when gpu field is True.

0

EVRC (not applicable in this release

Percentage of channels to be allocated for EVRC codec (0-100)

Applicable only when gpu field is True.

0

EVRCB (not applicable in this release)

Percentage of channels to be allocated for EVRCB codec (0-100)

Applicable only when gpu field is True.

0

G729

Percentage of channels to be allocated for G729 codec (0-100)

Applicable only when gpu field is True.

0

G722

Percentage of channels to be allocated for G722 codec (0-100)

Applicable only when gpu field is True.

0

 

 

 


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:

 

Table : OS Configuration for Compute Node with GPU Device

Step
Action
Notes
1

Edit /etc/sysconfig/grub and ensure that the following parameters are populated:

intel_iommu=on iommu=pt rdblacklist=nouveau

 

  • Enables kernel support for PCIe passthrough.
  • Blacklists opensource NVIDIA driver (nouveau) from loading on the host.
2

Update grub using the following command:

grub2-mkconfig -o /etc/grub2.cfg
3

Create /etc/modprobe.d/nouveau.conf file with the following contents:

blacklist nouveau
Blacklists opensource NVIDIA driver (nouveau) from loading on the host.
4Reboot the compute node. 
 

 

Table : Openstack Configuration for Compute Node with GPU Device

Step
Action
1

Add a PCI alias for the GPU device in /etc/nova/nova.conf.

For V100:

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

Note: Flavors that make use of this PCI device will refer to this PCI alias.

2

Add an entry for the GPU device to the existing PCIe whitelist entries in /etc/nova/nova.conf.

For V100:

pci_passthrough_whitelist=[{"devname": "p5p1", "physical_network": "sriov_1"}, {"devname": "p5p2", "physical_network": "sriov_2"},{"devname": "p6p1", "physical_network": "sriov_3"},{"devname": "p6p2", "physical_network": "sriov_4"}, {"vendor_id":"10de","product_id":"1db4"}]

Note: Whitelist PCI device for use in OpenStack.

3

Restart nova-compute service:

systemctl restart OpenStack-nova-compute.service

 

 

Table : Openstack Configuration for Controller Node

Step
Procedure
1

Ensure PciPassthroughFilter and NumaTopologyFilter are added to scheduler_default_filters list in /etc/nova/nova.conf file.

Note: Enables nova to instantiate instances with CPU resources from the same NUMA as that of the PCI devices to be used.

2

Add PCI alias for the GPU device in /etc/nova/nova.conf file

For V100:

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

Note:PCI alias will be referred to by flavors that make use of this PCI device

3

Restart nova-api service

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.

Note

This is a sample benchmark. Ribbon does not mandate the use of the processors shown here.

Table : Flavor Creation Guideline for GPU T-SBC Instances

Property
For V100
VCPUs20
RAM25 GiB
Root Disk (min)65 GiB
 

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

Table : Metadata Key Values

Key
Value for V100
Remark
hw:cpu_policydedicatedEnsures guest vCPUs are pinned to host cpus for performance.
hw:numa_nodes1Ensures host cpus of a single NUMA node are used in the instance for performance.
hw:cpu_thread_policypreferThis setting allocates each vCPU on thread siblings of physical CPUs.
hw:cpu_max_sockets1This setting defines how KVM exposes the sockets and cores to the guest.
pci_passthrough:aliasv100gpu:1Ensures NVIDIA PCIe devices are attached to the instance.
 

Configuring the SBC for Invoking T-SBC

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

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:

Table : Creating a DSP Cluster

StepAction
1Log on to the EMA and then click the All tab.
2

In the navigation pane, click System > DSBC > Cluster > Type and add the T-SBC node entry by selecting DSP:

3Click in the FQDN field and then add the corresponding FQDN for the T-SBC created in the T-SBC configuration.
4Click Save.
5

Refer to System Provisioning - Packet Service Profile for configuration changes that must be made on the S-SBC to enable transcoding.

Note: In GPU T-SBCs, the required codecs and their percentages must be provisioned in the Heat template as described in the previous section. This provisioning is fixed for the lifetime of the application. All members of a single T-SBC cluster should follow the same codec provisioning values.

Note:

The GPU transcoding solution currently does not support more than one non-G711 transcodable codec per leg on a trunk group. Therefore when configuring Packet Service Profiles, do not configure multiple non-G711 codecs on a single leg (This Leg/Other Leg parameters) when specifying the Codecs Allowed For Transcoding within Packet To Packet Control. Refer to Packet Service Profile - CLI or Packet To Packet Control - Codecs Allowed For Transcoding (EMA).

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 Invoke 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.

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