Re: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated driver

["Walukiewicz, Miroslaw" <Miroslaw.Walukiewicz@intel.com>]

Thank you for explanation. 

I have a few  questions regarding the setup flow yet:

1. Why we need this step:
>   3. Setup a flow director rule to distribute packets with source ip
> > > > > >      0.0.0.0 to rxq No.0
> > > > > >   > ethtool -N eth0  flow-type udp4 src-ip 0.0.0.0 action 0


2. You presented the filter setup for receiving all udp4 packets on specific queue
> > > > > >   5. Setup a flow director rule to distribute packets with source ip
> > > > > >      1.1.1.1 to rxq No.32. This needs to be done after testpmd starts.
> > > > > >   > ethtool -N eth0 flow-type udp4 src-ip 1.1.1.1 action 32

How to configure flow director to receive all packets with dst-ip = 1.1.1.1 on qpair=32?
Will TCP SYN packets caught by such filter setup?

3.  Do we have a possibility to setup a rule like:
Forward all TCPv4 rx packets with dst-ip =1.1.1.1 and TCP port 2222 to qpair=32 including SYN packets?

3. In your application example you present that qpair number (32) is known before start of application
> > > > > >   > ./x86_64-native-linuxapp-gcc/app/testpmd -c 0x3 -n 4 \
> > > > > >   >  --vdev=rte_bifurc,iface=eth0,qpairs=1 -- \
> > > > > >   >  -i --rxfreet=32 --txfreet=32 --txrst=32

Is there a possibility to dynamic queue allocation? I ask about API.
 I mean dynamic attaching and detaching queue from application level and not specifying the numbers in the command line.

4. Is there a possibility to create a rule with perfect match and directing the packets to the specific queue.
I mean here a rule like:
Forward all TCPv4 rx packets with dst-ip=1.1.1.1 src-ip=2.2.2.2 dst-port=2222 src-port=1234 to queue 33

Regards,

Mirek

> -----Original Message-----
> From: Zhou, Danny
> Sent: Tuesday, November 25, 2014 4:23 PM
> To: Richardson, Bruce; Walukiewicz, Miroslaw
> Cc: dev@dpdk.org
> Subject: RE: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated driver
> 
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson
> > Sent: Tuesday, November 25, 2014 11:03 PM
> > To: Walukiewicz, Miroslaw
> > Cc: dev@dpdk.org
> > Subject: Re: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated driver
> >
> > On Tue, Nov 25, 2014 at 02:57:13PM +0000, Walukiewicz, Miroslaw wrote:
> > > Thank you Bruce for explanation of the idea.
> >
> > Actually, credit goes to Steve Liang, not me, for the explanation. :-)
> >
> > >
> > > I have question regarding TCP SYN packets? Do you have any idea how to
> share the TCP SYN requests between kernel and
> > user-space application?
> >
> > As I'm giving the credit to Steve, I'll also pass the buck for answering that
> > question to him too! :-)
> >
> > /Bruce
> 
> On ixgbe' Rx queuing flow, match SYN filter stage is prior to Flow Director
> filter stage. When working at bifurcated driver support mode,
> DPDK cannot access those NIC registers except for the ones that are used to
> rx/tx packets for assigned rx/tx queue pairs. So basically it really
> depends on user to use ethtool or other interface to setup SYN filter via
> ixgbe bifurcated driver. User can distribute TCP SYN packets to
> kernel bifurcated driver owned rx queues or DPDK owned rx queues, for the
> latter case, DPDK can still push them back to kernel via KNI if DPDK
> does not want to use them. If you have a user space TCP/IP stacks on top of
> DPDK, you can push them to the upper level stack rather instead.
> 
> > >
> > > Regards,
> > >
> > > Mirek
> > >
> > > > -----Original Message-----
> > > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce
> Richardson
> > > > Sent: Tuesday, November 25, 2014 3:30 PM
> > > > To: Neil Horman
> > > > Cc: dev@dpdk.org
> > > > Subject: Re: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated
> driver
> > > >
> > > > On Tue, Nov 25, 2014 at 09:23:16AM -0500, Neil Horman wrote:
> > > > > On Tue, Nov 25, 2014 at 10:11:16PM +0800, Cunming Liang wrote:
> > > > > >
> > > > > > This is a RFC patch set to support "bifurcated driver" in DPDK.
> > > > > >
> > > > > >
> > > > > > What is "bifurcated driver"?
> > > > > > ===========================
> > > > > >
> > > > > > The "bifurcated driver" stands for the kernel NIC driver that
> supports:
> > > > > >
> > > > > > 1. on-demand rx/tx queue pairs split-off and assignment to user
> space
> > > > > >
> > > > > > 2. direct NIC resource(e.g. rx/tx queue registers) access from user
> space
> > > > > >
> > > > > > 3. distributing packets to kernel or user space rx queues by
> > > > > >    NIC's flow director according to the filter rules
> > > > > >
> > > > > > Here's the kernel patch set to support.
> > > > > > http://comments.gmane.org/gmane.linux.network/333615
> > > > > >
> > > > > >
> > > > > > Usage scenario
> > > > > > =================
> > > > > >
> > > > > > It's well accepted by industry to use DPDK to process fast path
> packets in
> > > > > > user space in a high performance fashion, meanwhile processing
> slow
> > > > path
> > > > > > control packets in kernel space is still needed as those packets
> usually
> > > > > > rely on in_kernel TCP/IP stacks and/or socket programming
> interface.
> > > > > >
> > > > > > KNI(Kernel NIC Interface) mechanism in DPDK is designed to meet
> this
> > > > > > requirement, with below limitation:
> > > > > >
> > > > > >   1) Software classifies packets and distributes them to kernel via
> DPDK
> > > > > >      software rings, at the cost of significant CPU cycles and memory
> > > > bandwidth.
> > > > > >
> > > > > >   2) Memory copy packets between kernel' socket buffer and mbuf
> brings
> > > > > >      significant negative performance impact to KNI performance.
> > > > > >
> > > > > > The bifurcated driver provides a alternative approach that not only
> > > > offloads
> > > > > > flow classification and distribution to NIC but also support packets
> > > > zero_copy.
> > > > > >
> > > > > > User can use standard ethtool to add filter rules to the NIC in order
> to
> > > > > > distribute specific flows to the queues only accessed by kernel
> driver and
> > > > > > stack, and add other rules to distribute packets to the queues
> assigned to
> > > > > > user-space.
> > > > > >
> > > > > > For those rx/tx queue pairs that directly accessed from user space,
> > > > > > DPDK takes over the packets rx/tx as well as corresponding DMA
> > > > operation
> > > > > > for high performance packet I/O.
> > > > > >
> > > > > >
> > > > > > What's the impact and change to DPDK
> > > > > > ======================================
> > > > > >
> > > > > > DPDK usually binds PCIe NIC devices by leveraging kernel' user
> space
> > > > driver
> > > > > > mechanism UIO or VFIO to map entire NIC' PCIe I/O space of NIC to
> user
> > > > space.
> > > > > > The bifurcated driver PMD talks to a NIC interface using raw socket
> APIs
> > > > and
> > > > > > only mmap() limited I/O space (e.g. certain 4K pages) for accessing
> > > > involved
> > > > > > rx/tx queue pairs. So the impact and changes mainly comes with
> below:
> > > > > >
> > > > > > - netdev
> > > > > >     DPDK needs to create a af_packet socket and bind it to a
> bifurcated
> > > > netdev.
> > > > > >     The socket fd will be used to request 'queue pairs info',
> > > > > >     'split/return queue pairs' and etc. The PCIe device ID, netdev MAC
> > > > address,
> > > > > >     numa info are also from the netdev response.
> > > > > >
> > > > > > - PCIe device scan and driver probe
> > > > > >     netdev provides the PCIe device ID information. Refer to the
> device ID,
> > > > > >     the correct driver should be used. And for such netdev device,
> the
> > > > creation
> > > > > >     of PCIe device is no longer from scan but the on-demand
> assignment.
> > > > > >
> > > > > > - PCIe BAR mapping
> > > > > >     "bifurcated driver" maps several pages for the queue pairs.
> > > > > >     Others BAR register space maps to a fake page. The BAR mapping
> go
> > > > through
> > > > > >     mmap on sockfd. Which is a little different from what UIO/VFIO
> does.
> > > > > >
> > > > > > - PMD
> > > > > >     The PMD will no longer really initialize and configure NIC.
> > > > > >     Instead, it only takes care the queue pair setup, rx_burst and
> tx_burst.
> > > > > >
> > > > > > The patch uses eal '--vdev' parameter to assign netdev iface name
> and
> > > > number of
> > > > > > queue pairs. Here's a example about how to configure the
> bifurcated
> > > > driver and
> > > > > > run DPDK testpmd with bifurcated PMD.
> > > > > >
> > > > > >   1. Set promisc mode
> > > > > >   > ifconfig eth0 promisc
> > > > > >
> > > > > >   2. Turn on fdir
> > > > > >   > ethtool -K eth0 ntuple on
> > > > > >
> > > > > >   3. Setup a flow director rule to distribute packets with source ip
> > > > > >      0.0.0.0 to rxq No.0
> > > > > >   > ethtool -N eth0  flow-type udp4 src-ip 0.0.0.0 action 0
> > > > > >
> > > > > >   4. Run testpmd on netdev 'eth0' with 1 queue pair.
> > > > > >   > ./x86_64-native-linuxapp-gcc/app/testpmd -c 0x3 -n 4 \
> > > > > >   >  --vdev=rte_bifurc,iface=eth0,qpairs=1 -- \
> > > > > >   >  -i --rxfreet=32 --txfreet=32 --txrst=32
> > > > > >   Note:
> > > > > >     iface and qpairs arguments above specify the netdev interface
> name
> > > > and
> > > > > >     number of qpairs that user space request from the "bifurcated
> driver"
> > > > > >     respectively.
> > > > > >
> > > > > >   5. Setup a flow director rule to distribute packets with source ip
> > > > > >      1.1.1.1 to rxq No.32. This needs to be done after testpmd starts.
> > > > > >   > ethtool -N eth0 flow-type udp4 src-ip 1.1.1.1 action 32
> > > > > >
> > > > > > Below illustrates the detailed changes in this patch set.
> > > > > >
> > > > > > eal
> > > > > > --------
> > > > > > The first two patches are all about the eal API declaration and Linux
> > > > version
> > > > > > definition to support af_packet socket and verbs of bifurcated
> netdev.
> > > > > > Those APIs include the verbs like open, bind, (un)map, split/retturn,
> > > > map_umem.
> > > > > > And other APIs like set_pci, get_ifinfo and get/put_devargs which
> help to
> > > > > > generate pci device from bifurcated netdev and get basic netdev
> info.
> > > > > >
> > > > > > The third patch is used to allow probing driver on the PCIe VDEV
> created
> > > > from
> > > > > > a NIC interface driven by "bifurcated driver". It defines a new flag
> > > > > > 'RTE_PCI_DRV_BIFURC' used for direct ring access PMD.
> > > > > >
> > > > > > librte_bifurc
> > > > > > ---------------
> > > > > > The library is used as a VDEV bus driver to scan '--vdev=rte_bifurc'
> VDEV
> > > > > > from eal command-line. It generates the PCIe VDEV device ready
> for
> > > > further
> > > > > > driver probe. It maintains the bifurcated device information include
> > > > sockfd,
> > > > > > hwaddr, mtu, qpairs, iface_name. It's used for other direct ring
> access
> > > > PMD
> > > > > > to apply for bifurcated device info.
> > > > > >
> > > > > > direct ring access PMD
> > > > > > -------------------------
> > > > > > The patch provides direct ring access PMD for ixgbe. Comparing to
> the
> > > > normal
> > > > > > PMD ixgbe, it uses 'RTE_PCI_DRV_BIFURC' flag during self
> registration.
> > > > > > It mostly reuses the existing PMD ops to avoid re-implementing
> > > > everything
> > > > > > from scratch. And it also modifies the rx/tx_queue_setup to allow
> queue
> > > > > > setup from any queue offset.
> > > > > >
> > > > > > Supported NIC driver
> > > > > > ========================
> > > > > >
> > > > > > The "bifurcated driver" kernel patch only supports "ixgbe" driver at
> the
> > > > moment,
> > > > > > so this RFC patch also provides "ixgbe" PMD via direct-mapped rings
> as
> > > > sample.
> > > > > > The support for 40GE(i40e) will be added in the future.
> > > > > >
> > > > > > In addition, for those multi-queues enabled NIC with flow director
> > > > capability
> > > > > > to do perform packet classification and distribution, there's no
> special
> > > > > > technical gap to provide bifurcated driver approach support.
> > > > > >
> > > > > > Limitation
> > > > > > ============
> > > > > >
> > > > > > By using "bifurcated driver", user space only takes over the DMA
> > > > operation.
> > > > > > For those NIC configure setting, it's out of control from user space
> PMD.
> > > > > > All the NIC setting including add/del filter rules need to be done by
> > > > > > standard Linux network tools(e.g. ethtool).
> > > > > > So the feature support really depend on how much are supported
> by
> > > > ethtool.
> > > > > >
> > > > > >
> > > > > > Any questions, comments and feedback are welcome.
> > > > > >
> > > > > >
> > > > > > -END-
> > > > > >
> > > > > > Signed-off-by: Cunming Liang <cunming.liang@intel.com>
> > > > > > Signed-off-by: Danny Zhou <danny.zhou@intel.com>
> > > > > >
> > > > > > *** BLURB HERE ***
> > > > > >
> > > > > > Cunming Liang (6):
> > > > > >   eal: common direct ring access API
> > > > > >   eal: direct ring access support by linux af_packet
> > > > > >   pci: allow VDEV as pci device during device driver probe
> > > > > >   bifurc: add driver to scan bifurcated netdev
> > > > > >   ixgbe: rx/tx queue stop bug fix
> > > > > >   ixgbe: PMD for bifurc ixgbe net device
> > > > > >
> > > > > >  config/common_linuxapp                         |   5 +
> > > > > >  lib/Makefile                                   |   1 +
> > > > > >  lib/librte_bifurc/Makefile                     |  58 +++++
> > > > > >  lib/librte_bifurc/rte_bifurc.c                 | 284
> +++++++++++++++++++++
> > > > > >  lib/librte_bifurc/rte_bifurc.h                 |  90 +++++++
> > > > > >  lib/librte_eal/common/Makefile                 |   5 +
> > > > > >  lib/librte_eal/common/include/rte_pci.h        |   4 +
> > > > > >  lib/librte_eal/common/include/rte_pci_bifurc.h | 186
> ++++++++++++++
> > > > > >  lib/librte_eal/linuxapp/eal/Makefile           |   1 +
> > > > > >  lib/librte_eal/linuxapp/eal/eal_pci.c          |  42 ++--
> > > > > >  lib/librte_eal/linuxapp/eal/eal_pci_bifurc.c   | 336
> > > > +++++++++++++++++++++++++
> > > > > >  lib/librte_ether/rte_ethdev.c                  |   3 +-
> > > > > >  lib/librte_pmd_ixgbe/Makefile                  |  13 +-
> > > > > >  lib/librte_pmd_ixgbe/ixgbe_bifurcate.c         | 303
> > > > ++++++++++++++++++++++
> > > > > >  lib/librte_pmd_ixgbe/ixgbe_bifurcate.h         |  57 +++++
> > > > > >  lib/librte_pmd_ixgbe/ixgbe_rxtx.c              |  44 +++-
> > > > > >  lib/librte_pmd_ixgbe/ixgbe_rxtx.h              |  10 +
> > > > > >  mk/rte.app.mk                                  |   6 +
> > > > > >  18 files changed, 1421 insertions(+), 27 deletions(-)
> > > > > >  create mode 100644 lib/librte_bifurc/Makefile
> > > > > >  create mode 100644 lib/librte_bifurc/rte_bifurc.c
> > > > > >  create mode 100644 lib/librte_bifurc/rte_bifurc.h
> > > > > >  create mode 100644
> lib/librte_eal/common/include/rte_pci_bifurc.h
> > > > > >  create mode 100644 lib/librte_eal/linuxapp/eal/eal_pci_bifurc.c
> > > > > >  create mode 100644 lib/librte_pmd_ixgbe/ixgbe_bifurcate.c
> > > > > >  create mode 100644 lib/librte_pmd_ixgbe/ixgbe_bifurcate.h
> > > > > >
> > > > > > --
> > > > > > 1.8.1.4
> > > > > >
> > > > > >
> > > > > AIUI, the bifurcated driver hasn't yet been accepted upstream, has it?
> > > > Given
> > > > > that, I don't think its wise to pull this in yet ahead of the kernel work,
> as
> > > > > there may still be kernel side changes that the user space pmd will
> have to
> > > > > adapt to.
> > > > > Neil
> > > > >
> > > > Hence the RFC nature of the patch, I believe. :-) Before the kernel part
> hits
> > > > the
> > > > main kernel tree we can at least discuss the overall direction to be
> taken for
> > > > this driver because it's significantly different that any other HW driver.
> > > >
> > > > /Bruce