>From: Bie, Tiwei >Sent: Friday, December 8, 2017 4:19 AM >To: Kavanagh, Mark B <[email protected]> >Cc: [email protected]; [email protected]; [email protected]; >[email protected]; [email protected]; Mooney, Sean K ><[email protected]>; Stokes, Ian <[email protected]>; >[email protected]; Fischetti, Antonio <[email protected]>; Loftus, >Ciara <[email protected]>; Mcnamara, John <[email protected]>; >[email protected] >Subject: Re: [ovs-dev][PATCH V5 1/2] netdev-dpdk: DPDK v17.11 upgrade > >On Thu, Dec 07, 2017 at 05:45:36PM +0000, Mark Kavanagh wrote: >> This commit adds support for DPDK v17.11: >> - minor updates to accomodate DPDK API changes >> - update references to DPDK version in Documentation >> - update DPDK version in travis' linux-build script >> - document DPDK v17.11 virtio driver bug >> >> Signed-off-by: Mark Kavanagh <[email protected]> >> Acked-by: Maxime Coquelin <[email protected]> >> Acked-by: Ciara Loftus <[email protected]> >> Acked-by: Jan Scheurich <[email protected]> >> Tested-by: Jan Scheurich <[email protected]> >> Tested-by: Guoshuai Li <[email protected]> >> --- >[...] >> >> -.. _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. >> + >> + 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. >> + > >I'm not very familiar with the use case related to ovs. >The bug you mentioned only affects the vector Rx of virtio >PMD, while the vector Rx won't be enabled by default, as >it has the most limitations among the three Rx functions >in virtio PMD, e.g. it's not able to handle the mergeable >rxbuf (VIRTIO_NET_F_MRG_RXBUF) which is enabled by default >and commonly used. But I'm not sure whether the vector Rx >of virtio PMD is commonly used in ovs related cases.
Hi Tiwei, For optimal performance, in OvS we recommend that users disable mergeable buffers; as such, I’d imagine that the vector Rx function will be used in most cases. > >If it's really necessary to document a PMD bug of DPDK in >ovs, I think we should provide more accurate info in this >warning, e.g. warn users not to use vector Rx when using >virtio PMD instead of warning them not to use DPDK 17.11. Agreed - I just saw the mail exchange between yourself and Kevin regarding same. I'll update the documentation accordingly in v6. Thanks and best, Mark > >Thanks, >Tiwei _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
