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John DeNisco06dcd452018-07-26 12:45:10 -04001.. _vhost05:
2
3Limitations
4-----------
5There are some limitations when using the qemu vhost driver. Some are described in this section.
6
7Performance
8^^^^^^^^^^^
9
10VPP performance with vHost is limited by the Qemu vHost driver. FD.io VPP 18.04 CSIT vHost testing
11shows with 2 threads, 2 cores and a Queue size of 1024 the maximum NDR throughput was about 7.5 Mpps.
12This is about the limit at this time.
13
Nathan Skrzypczak9ad39c02021-08-19 11:38:06 +020014For all the details on the CSIT VM vhost connection refer to the
John DeNisco06dcd452018-07-26 12:45:10 -040015`CSIT VM vHost performance tests <https://docs.fd.io/csit/rls1804/report/vpp_performance_tests/packet_throughput_graphs/vm_vhost.html>`_.
16
17
18Features
19^^^^^^^^
20
21These are the features not supported with FD.io VPP vHost.
22
23* 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.
24* VPP vHost implementation does not support checksum or transmit segmentation offload.
25* VPP vHost implementation does not support packet receive filtering feature for controlling receive traffic.