[ovs-discuss] OVS-DPDK - Very poor performance when connected to namespace/container

Darrell Ball dball at vmware.com
Fri Jun 16 17:25:05 UTC 2017



On 6/16/17, 10:01 AM, "Mooney, Sean K" <sean.k.mooney at intel.com> wrote:

    
    > -----Original Message-----
    > From: Darrell Ball [mailto:dball at vmware.com]
    > Sent: Friday, June 16, 2017 5:53 PM
    > To: Gray, Mark D <mark.d.gray at intel.com>; Mooney, Sean K
    > <sean.k.mooney at intel.com>; Avi Cohen (A) <avi.cohen at huawei.com>;
    > users at dpdk.org; ovs-discuss at openvswitch.org
    > Subject: Re: [ovs-discuss] OVS-DPDK - Very poor performance when
    > connected to namespace/container
    > 
    > This should be quite a bit better than the AF_PACKET PMD.
    > This becomes available in 17.08 and is important, it would be nice to
    > get into the next OVS release.
    [Mooney, Sean K] 
    Virtio user will work only if you have dpdk in the container/namespce correct?
    The vhsot frontend is being provisioned by isided the dpdk vhost driver in the application.

Yes, it requires more effort on the install/config side, but may be worth it in many cases. 

    
    I agree that is the way to go if your application support dpdk, if not you would need
    To use one of the other vdevs.
    
    > 
    > Also, any existing data on the performance advantage of AF_PACKET PMD
    > with single queue ?
    [Mooney, Sean K] I would be interested in seeing this also if anyone has data to share.
    > 
    > Darrell
    > 
    > 
    > On 6/16/17, 1:56 AM, "ovs-discuss-bounces at openvswitch.org on behalf of
    > Gray, Mark D" <ovs-discuss-bounces at openvswitch.org on behalf of
    > mark.d.gray at intel.com> wrote:
    > 
    >     Hi Avi,
    > 
    >     The other option is to use virtio-use
    > (https://urldefense.proofpoint.com/v2/url?u=http-
    > 3A__dpdk.org_doc_guides_howto_virtio-5Fuser-5Ffor-5Fcontainer-
    > 5Fnetworking.html&d=DwICAg&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-
    > uZnsw&m=_7l_cdKorhow4zRqAu5lnTmzv9Etgn5TX7D6P0pqP8c&s=ThmUVGZC2M1LBAIhn
    > vs-5OiSZz7ywpez2Qj70BrQjoM&e= ) which gives dpdk-like performance to a
    > dpdk application running in a container. The configuration for ovs-dpdk
    > has not been documented but it is possible to use (as a vdev).
    > 
    >     Also, I have dropped the dpdk-ovs at lists.01.org mail address as this
    > is for the discontinued ovdk project.
    > 
    >     Mark
    > 
    >     > -----Original Message-----
    >     > From: Dpdk-ovs [mailto:dpdk-ovs-bounces at lists.01.org] On Behalf
    > Of
    >     > Mooney, Sean K
    >     > Sent: Thursday, June 15, 2017 12:33 PM
    >     > To: Avi Cohen (A) <avi.cohen at huawei.com>; dpdk-ovs at lists.01.org;
    >     > users at dpdk.org; ovs-discuss at openvswitch.org
    >     > Subject: Re: [Dpdk-ovs] OVS-DPDK - Very poor performance when
    >     > connected to namespace/container
    >     >
    >     >
    >     >
    >     > > -----Original Message-----
    >     > > From: Avi Cohen (A) [mailto:avi.cohen at huawei.com]
    >     > > Sent: Thursday, June 15, 2017 9:50 AM
    >     > > To: Mooney, Sean K <sean.k.mooney at intel.com>; dpdk-
    > ovs at lists.01.org;
    >     > > users at dpdk.org; ovs-discuss at openvswitch.org
    >     > > Subject: RE: OVS-DPDK - Very poor performance when connected to
    >     > > namespace/container
    >     > >
    >     > >
    >     > >
    >     > > > -----Original Message-----
    >     > > > From: Mooney, Sean K [mailto:sean.k.mooney at intel.com]
    >     > > > Sent: Thursday, 15 June, 2017 11:24 AM
    >     > > > To: Avi Cohen (A); dpdk-ovs at lists.01.org; users at dpdk.org;
    > ovs-
    >     > > > discuss at openvswitch.org
    >     > > > Cc: Mooney, Sean K
    >     > > > Subject: RE: OVS-DPDK - Very poor performance when connected
    > to
    >     > > > namespace/container
    >     > > >
    >     > > >
    >     > > >
    >     > > > > -----Original Message-----
    >     > > > > From: Dpdk-ovs [mailto:dpdk-ovs-bounces at lists.01.org] On
    > Behalf Of
    >     > > > > Avi Cohen (A)
    >     > > > > Sent: Thursday, June 15, 2017 8:14 AM
    >     > > > > To: dpdk-ovs at lists.01.org; users at dpdk.org;
    >     > > > > ovs-discuss at openvswitch.org
    >     > > > > Subject: [Dpdk-ovs] OVS-DPDK - Very poor performance when
    >     > > > > connected to namespace/container
    >     > > > >
    >     > > > > Hello   All,
    >     > > > > I have OVS-DPDK connected to a namespace via veth pair
    > device.
    >     > > > >
    >     > > > > I've got a very poor performance - compared to normal OVS
    > (i.e. no
    >     > > > > DPDK).
    >     > > > > For example - TCP jumbo pkts throughput: normal OVS  ~
    > 10Gbps ,
    >     > > OVS-
    >     > > > > DPDK 1.7 Gbps.
    >     > > > >
    >     > > > > This can be explained as follows:
    >     > > > > veth is implemented in kernel - in OVS-DPDK data is
    > transferred
    >     > > from
    >     > > > > veth to user space while in normal OVS we save this
    > transfer
    >     > > > [Mooney, Sean K] that is part of the reason, the other reson
    > this is
    >     > > > slow and The main limiter to scalling adding veth pairs or
    > ovs
    >     > > > internal port to ovs with dpdk is That these linux kernel
    > ports are
    >     > > > not processed by the dpdk pmds. They are server by the Ovs-
    > vswitchd
    >     > > > main thread via a fall back to the non dpdk acclarated netdev
    >     > > implementation.
    >     > > > >
    >     > > > > Is there any other device to connect to namespace ?
    > something like
    >     > > > > vhost-user ? I understand that vhost-user cannot be used
    > for
    >     > > > > namespace
    >     > > > [Mooney, Sean K] I have been doing some experiments in this
    > regard.
    >     > > > You should be able to use the tap, pcap or afpacket pmd to
    > add a
    >     > > > vedv that will improve Performance. I have seen some strange
    > issue
    >     > > > with
    >     > > the
    >     > > > tap pmd that cause packet to be drop By the kernel on tx on
    > some
    >     > > ports
    >     > > > but not others so there may be issues with that dirver.
    >     > > >
    >     > > > Previous experiment with libpcap seemed to work well with ovs
    > 2.5
    >     > > > but I have not tried it With ovs 2.7/master since the
    > introduction
    >     > > > of generic vdev support at runtime. Previously vdevs And to
    > be
    >     > > > allocated
    >     > > using the dpdk args.
    >     > > >
    >     > > > I would try following the af_packet example here
    >     > > >
    >     > >
    >     > https://urldefense.proofpoint.com/v2/url?u=https-
    > 3A__github.com_openvswitch_ovs_blob_b132189d8456f38f3ee139f126d68&d=DwI
    > CAg&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-
    > uZnsw&m=_7l_cdKorhow4zRqAu5lnTmzv9Etgn5TX7D6P0pqP8c&s=REyqxTB8Gd9BnEtet
    > H_Aul0OgyyGK0DFhKl3tFGzOGI&e=
    >     > 0
    >     > > > 9 01a9ee9a8/Documentation/howto/dpdk.rst#vdev-support
    >     > > >
    >     > > [Avi Cohen (A)]
    >     > > Thank you Mooney, Sean K
    >     > > I already tried to connect the namespace with a tap device (see
    > 1 & 2
    >     > > below)  - and got the worst performance  for some reason the
    > packet
    >     > > is cut to default MTU inside the  OVS-DPDK which transmit the
    > packet
    >     > > to its peer. - although all interfaces MTU were set to 9000.
    >     > >
    >     > >  1. ovs-vsctl add-port $BRIDGE tap1 -- set Interface tap1
    >     > > type=internal
    >     > >
    >     > >  2. ip link set tap1 netns ns1 // attach it to namespace
    >     > [Mooney, Sean K] this is not using the dpdk tap pmd , internal
    > port and veth
    >     > ports If added to ovs will not be accelerated by dpdk unless you
    > use a vdev to
    >     > attach them.
    >     > >
    >     > > I'm looking at your link to create a virtual PMD with vdev
    > support - I
    >     > > see there a creation of a virtual PMD device , but I'm not sure
    > how
    >     > > this is connected to the namespace ?  what device should I
    > assign to
    >     > > the namespace ?
    >     > [Mooney, Sean K]
    >     > You would use it as follows
    >     >
    >     > ip tuntap add dev tap1 mode tap
    >     >
    >     > ovs-vsctl add-port br0 tap1 -- set Interface tap1 type=dpdk \
    >     > options:dpdk-devargs=eth_af_packet0,iface=tap1
    >     >
    >     > ip link set tap1 netns ns1
    >     >
    >     > ip netns exec ns1 ifconfig 192.168.1.1/24 up
    >     >
    >     > in general though if you are using ovs-dpdk you should avoid
    > using network
    >     > namespace and the kernel where possible but the above should
    > improve
    >     > you performance. One caveat, the amount of vdev+phyical
    > interfaces is
    >     > limited by how dpdk is compiled by default to 32 devices but it
    > can be
    >     > increased to 256 if required.
    >     >
    >     > >
    >     > > Best Regards
    >     > > avi
    >     > >
    >     > > > if you happen to be investigating this for use with openstack
    >     > > > routers we Are currently working on a way to remove the use
    > of
    >     > > > namespace entirely for dvr when using The default neutron
    > agent and
    >     > > > sdn controllers such as ovn already provide that
    > functionality.
    >     > > > >
    >     > > > > Best Regards
    >     > > > > avi
    >     > > > > _______________________________________________
    >     > > > > Dpdk-ovs mailing list
    >     > > > > Dpdk-ovs at lists.01.org
    >     > > > > https://urldefense.proofpoint.com/v2/url?u=https-
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