>From: Jan Scheurich [mailto:[email protected]] >Sent: Friday, December 8, 2017 10:01 AM >To: Kavanagh, Mark B <[email protected]>; [email protected] >Cc: [email protected]; [email protected]; [email protected]; >Mooney, Sean K <[email protected]>; Stokes, Ian <[email protected]>; >[email protected]; Fischetti, Antonio <[email protected]>; Bie, Tiwei ><[email protected]>; Loftus, Ciara <[email protected]> >Subject: RE: [ovs-dev][PATCH V5 1/2] netdev-dpdk: DPDK v17.11 upgrade > >> From: Mark Kavanagh [mailto:[email protected]] >> Sent: Thursday, 07 December, 2017 18:46 >> >> #. (Optional) Configure DPDK as a shared library >> @@ -583,7 +583,21 @@ Limitations >> The latest list of validated firmware versions can be found in the `DPDK >> release notes`_. >> >> -.. _DPDK release notes: >http://dpdk.org/doc/guides/rel_notes/release_17_05.html >> +.. _DPDK release notes: >http://dpdk.org/doc/guides/rel_notes/release_17_11.html >> + >> +- The DPDK v17.11 virtio net driver contains a bug that prevents guest DPDK >> + applications from receiving packets. This only occurs when guest-bound >traffic >> + is live before a DPDK application is started within the guest, and where >two >> + or more forwarding cores are used. As such, it is not recommended for >guests >> + which execute DPDK applications to upgrade to DPDK v17.11. >> + >> + Note that this issue does not occur when guest network devices are >controlled >> + by the guest kernel. >
Hi Jan, Thanks for your comments - please find responses inline. Best, Mark >I don't think this aspect should be documented as a limitation of OVS. It is a >bug that can affect DPDK 17.11 guest applications under certain conditions. If >at all we should have the such a statement in the dpdk/vhost_user.rst document >(see below). Good point - I'll move this text to the vhost_user doc. > >I am missing a statement here that OVS-DPDK itself, when running in a VM with >virtio interfaces, can be affected by this bug of the virtio PMD. A work- >around until the bug is fixed could be to make sure mergeable rx buffers are >enabled for the virtio ports in Qemu and vhost backend on the host, so that >the virtio PMD does not use the faulty vector Rx function. Yes, Tiwei and Kevin have expressed the same - I'll address these comments in v6. > >> + >> + Details regarding the virtio driver bug are available on the `DPDK >mailing >> + list`_. >> + >> +.. _DPDK mailing list: http://dpdk.org/ml/archives/dev/2017- >December/082801.html >> >> Reporting Bugs >> -------------- >> diff --git a/Documentation/topics/dpdk/ring.rst >b/Documentation/topics/dpdk/ring.rst >> index ad9d7a5..8d0ede8 100644 >> --- a/Documentation/topics/dpdk/ring.rst >> +++ b/Documentation/topics/dpdk/ring.rst >> @@ -77,4 +77,4 @@ DPDK. However, this functionality was removed because: >> - :doc:`vhost-user interfaces <vhost-user>` are the defacto DPDK-based path >to >> guests >> >> -.. _DPDK documentation: >https://dpdk.readthedocs.io/en/v17.05/prog_guide/ring_lib.html >> +.. _DPDK documentation: >https://dpdk.readthedocs.io/en/v17.11/prog_guide/ring_lib.html >> diff --git a/Documentation/topics/dpdk/vhost-user.rst >b/Documentation/topics/dpdk/vhost-user.rst >> index 74ac06e..1a5de24 100644 >> --- a/Documentation/topics/dpdk/vhost-user.rst >> +++ b/Documentation/topics/dpdk/vhost-user.rst >> @@ -287,6 +287,11 @@ application in the VM. >> >> Support for DPDK in the guest requires QEMU >= 2.2 >> >> +.. important:: >> + >> + DPDK v17.11 virtio PMD contains a bug that affects testpmd/DPDK guest >> + applications. As such, guests should not upgrade to 17.11. > >If such a temporary bug warning is really wanted here, it needs to be more >qualified. Sure - I'll add additional detail in the next version. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
