| .. _vhost05: |
| |
| Limitations |
| ----------- |
| There are some limitations when using the qemu vhost driver. Some are described in this section. |
| |
| Performance |
| ^^^^^^^^^^^ |
| |
| VPP performance with vHost is limited by the Qemu vHost driver. FD.io VPP 18.04 CSIT vHost testing |
| shows with 2 threads, 2 cores and a Queue size of 1024 the maximum NDR throughput was about 7.5 Mpps. |
| This is about the limit at this time. |
| |
| For all the details on the CSIT VM vhost connection refer to the |
| `CSIT VM vHost performance tests <https://docs.fd.io/csit/rls1804/report/vpp_performance_tests/packet_throughput_graphs/vm_vhost.html>`_. |
| |
| |
| Features |
| ^^^^^^^^ |
| |
| These are the features not supported with FD.io VPP vHost. |
| |
| * VPP implements vHost in device mode only. VPP is intended to work with Qemu which implements vHost in driver mode, it does not implement vHost driver mode. |
| * VPP vHost implementation does not support checksum or transmit segmentation offload. |
| * VPP vHost implementation does not support packet receive filtering feature for controlling receive traffic. |