This document provides an overview of DPDK and steps to configure and troubleshoot DPDK for OVS in NFVIS.
DPDK stands for Data Plane Development Kit, is a set of libraries that improves data plane performance.
Starting 3.10.1 NFVIS release, DPDK for OVS is supported. 3.12.2 NFVIS release is recommended when using OVS-DPDK.
NOTE :
|
DPDK-OVS |
|
|
Service Chain Throughput |
Service Chain throughput near SRIOV, better than non-DPDK OVS |
|
NFVIS Default Cores + Additional CPU for dpdk function |
1+1 CPU <=16 core system 2+2 >16 core system 3+1GB mem in <=32GB system 4+2GB mem in <=64GB system 4+4GB mem in <=128GB system |
|
Driver requirements in VNF |
Virtio required |
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Supported Platforms ENCS UCSE, UCS-C, CSP5K |
Yes 3.10.1 onwards Yes 3.12.1 onwards |
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Caveats |
Packet /traffic capture : Not supported in DPDK. Span traffic on PNIC : Not supported in DPDK. After OVS-DPDK is enabled, it cannot be disabled as a individual feature. Only way to disable DPDK would be a factory reset. |
Configuration Steps
OVS-DPDK can be enabled via CLI or NFVIS GUI
Verify DPDK status via CLI or NFVIS GUI
‘show system settings dpdk-status’
For unconfiguring DPDK, factory reset must be used.
There are 3 factory reset options, each one disables DPDK
| Factory-default-reset-config | DPDK-enabled | networks retained | VNF deployment removed | Registered Images removed |
| all | No | No | Yes | Yes |
| all-except-images | No | No | Yes | No |
| all-except-images-connectivity | No | Yes | Yes | No |
Troubleshooting
There are 3 possible DPDK statuses when running the
‘show system settings dpdk-status’ command
- Enabled - DPDK has been enabled successfully and no further action required. No reboot required.
nfvis#show system settings-native dpdk-status
system settings-native dpdk-status enabled
- Error – When DPDK is enabled, but not enough CPU’s are reserved by the system or there is not enough contiguous Hugepage memory available, the status resolves into an error.
nfvis#show system settings-native dpdk-status
system settings-native dpdk-status enabled <-----Error
- Enabling – After DPDK is enabled and the DPDK status fails to resolve to ‘enabled’ or ‘error’, the status will show ‘enabling’.
nfvis#show system settings-native dpdk-status
system settings-native dpdk-status enabled <-----Enabling
In order to recover the system from an ‘enabling’ DPDK status
1.Collect the tech-support logs and report to TAC engineer
vm-lifecycle->host->diagnostics->Download Tech-support (tar file with all the log files)
2.Run ‘factory reset’
3.Enable DPDK again
*If after enabling DPDK initially, the status fails to resolve to ‘enabled’ or ‘error’ after 5 minutes, please collect the tech- support logs and report it to your TAC engineer.
Reference
Huge Pages overview
- Memory is generally allocated in chunks of 4KB (called pages)
- HugePages are memory chunks that are bigger than the default 4KB pages, such as 2MB.
- When a CPU looks up pages, it will first inspect TLB cache
- TLB can be accessed extremely fast
- TLB cache has a limited number of entries for pages.
- By increasing the size of the pages, we can use the TLB cache in a more efficient way.
- 4KB * 256 = 1024KB = 1MB
- 2MB * 256 = 512MB = 0.5GB
- Increase by factor of 512.
HugePages always stay in memory and cannot be swapped. Thus, as soon as HugePages get allocated they are not available to the overall system anymore, although they might not be used at the moment.
HugePages are always allocated by the free memory of the system, which can be less than the total available memory. However not all free memory can be allocated as HugePages there will always be a remains.
Troubleshoot : show system memory
Troubleshoot : show system mem-info
Troubleshoot : VM domain XML
For a VM to use HugePages, one must ensure that the XML extract depicted below is included inside the VM domain XML.
nfvis# support virsh dumpxml ROUTER
<domain type='kvm' id='1' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0’>
<qemu:commandline>
<qemu:arg value='-numa'/>
<qemu:arg value='node,memdev=mem'/>
<qemu:arg value='-mem-prealloc'/>
<qemu:arg value='-object'/>
<qemu:arg value='memory-backend-file,id=mem,size=4096M,mem-path=/dev/hugepages,share=on'/>
</qemu:commandline>
</domain>
If DPDK is enabled each newly deployed VM should include it. If this is not the case, check /var/log/esc/forever.log for any dpdk-related errors.
Troubleshoot : network xml
vNIC on network which is on service-bridge will have following configuration. Here vnic2 is on test-net, which belongs to service-bridge test-br. Notice though, the configuration doesn’t have any reference of test-br.
<interface type='vhostuser'>
<mac address='52:54:00:76:a4:88'/>
<source type='unix' path='/run/vhostfd/vnic2' mode='server'/>
<target dev='vnic2'/>
<model type='virtio'/>
<alias name='net1'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
</interface>
Verify vnic2 configuration on the bridge: test-br.
nfvis# support ovs vsctl show
92171152-1c1d-4d95-935a-f8dba97527b6
…..
Bridge test-br
Port test-br
Interface test-br
type: internal
Port "vnic2"
Interface "vnic2"
type: dpdkvhostuserclient
options: {vhost-server-path="/run/vhostfd/vnic2"}
…..
ovs_version: "2.9.2"
Logs - /var/log/esc/forever.log
VM Deployment log
2018-12-03T22:20:23.968Z - ^[[34mdebug^[[39m: Check if dpdk is enabled.
2018-12-03T22:20:23.968Z - ^[[34mdebug^[[39m: Executing: /opt/platform-config/dpdk.sh passing: enabled
2018-12-03T22:20:24.218Z - ^[[34mdebug^[[39m: DPDK Status: true
2018-12-03T22:20:24.219Z - ^[[34mdebug^[[39m: Check if network mgmt-net is dpdk backed.
2018-12-03T22:20:24.219Z - ^[[34mdebug^[[39m: Executing: /opt/platform-config/dpdk.sh passing: network,mgmt-net
2018-12-03T22:20:24.445Z - ^[[34mdebug^[[39m: Network: mgmt-net dpdk status: true
2018-12-03T22:20:24.446Z - ^[[34mdebug^[[39m: Check if dpdk is enabled.
2018-12-03T22:20:24.446Z - ^[[34mdebug^[[39m: Executing: /opt/platform-config/dpdk.sh passing: enabled
2018-12-03T22:20:24.694Z - ^[[34mdebug^[[39m: DPDK Status: true
2018-12-03T22:20:24.694Z - ^[[34mdebug^[[39m: Check if network mgmt-net is dpdk backed.
2018-12-03T22:20:24.696Z - ^[[34mdebug^[[39m: Executing: /opt/platform-config/dpdk.sh passing: network,mgmt-net
2018-12-03T22:20:24.900Z - ^[[34mdebug^[[39m: Network: mgmt-net dpdk status: true
2018-12-03T22:20:24.901Z - ^[[34mdebug^[[39m: Creating vnic vnic0 on network mgmt-net
2018-12-03T22:20:24.901Z - ^[[34mdebug^[[39m: Executing: '/opt/platform-config/dpdk.sh' passing: create,mgmt-net,vnic0
2018-12-03T22:20:25.533Z - ^[[34mdebug^[[39m: Vhost FD: /run/vhostfd/vnic0
Logs - /var/log/vhostuser.log
VM Deployment:
2018-12-11 01:01:30,299 DEBUG: Bridge: test-br
2018-12-11 01:01:30,299 DEBUG: Checking if bridge test-br is DPDK backed
2018-12-11 01:02:02,294 DEBUG: Removing port vnic6
2018-12-11 01:02:02,295 DEBUG: Finding bridge for port vnic6
2018-12-11 01:02:02,344 DEBUG: Bridge: test-br
2018-12-11 01:02:02,409 DEBUG: Removed port: vnic6
2018-12-11 01:02:20,575 DEBUG: Removing port vnic9
2018-12-11 01:02:20,575 DEBUG: Finding bridge for port vnic9
2018-12-11 01:02:20,638 DEBUG: Bridge: test-br
2018-12-11 01:02:20,701 DEBUG: Removed port: vnic9
