| Message ID | 20220527163643.130679-1-bruce.richardson@intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Thomas Monjalon |
| Headers | show |
| Series | [v2,1/2] doc/howto: rework section on virtio-user as exception path | expand |
| Context | Check | Description |
|---|---|---|
| ci/checkpatch | success | coding style OK |
Hi Bruce, > -----Original Message----- > From: Richardson, Bruce <bruce.richardson@intel.com> > Sent: Saturday, May 28, 2022 12:37 AM > To: dev@dpdk.org > Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; Xia, Chenbo > <chenbo.xia@intel.com>; Richardson, Bruce <bruce.richardson@intel.com> > Subject: [PATCH v2 1/2] doc/howto: rework section on virtio-user as > exception path > > This patch extensively reworks the howto guide on using virtio-user for > exception packets. Changes include: > > * rename "exceptional path" to "exception path" > * remove references to uio and just reference vfio-pci > * simplify testpmd command-lines, giving a basic usage example first > before adding on detail about checksum or TSO parameters > * give a complete working example showing traffic flowing through the > whole system from a testpmd loopback using the created TAP netdev > * replace use of "ifconfig" with Linux standard "ip" command > * other general rewording. > > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com> > > --- > v2: fix checkpatch warnings > --- > .../howto/virtio_user_as_exceptional_path.rst | 159 +++++++++++------- I agree with the renaming. And should we rename this file, and if possible, the attached img too. > 1 file changed, 100 insertions(+), 59 deletions(-) > > diff --git a/doc/guides/howto/virtio_user_as_exceptional_path.rst > b/doc/guides/howto/virtio_user_as_exceptional_path.rst > index ec021af399..100376c32d 100644 > --- a/doc/guides/howto/virtio_user_as_exceptional_path.rst > +++ b/doc/guides/howto/virtio_user_as_exceptional_path.rst > @@ -3,116 +3,157 @@ > > .. _virtio_user_as_exceptional_path: > > -Virtio_user as Exceptional Path > -=============================== > +Virtio_user as Exception Path > +============================= > > -The virtual device, virtio-user, was originally introduced with vhost- > user > -backend, as a high performance solution for IPC (Inter-Process > Communication) > +.. note:: > + > + This solution is only applicable to Linux systems. > + > +The virtual device, virtio-user, was originally introduced with the > vhost-user > +backend as a high performance solution for IPC (Inter-Process > Communication) > and user space container networking. > > -Virtio_user with vhost-kernel backend is a solution for exceptional path, > -such as KNI which exchanges packets with kernel networking stack. This > -solution is very promising in: > +Beyond this originally intended use, virtio-user can be used in > conjunction with the vhost-kernel > +backend as a solution for dealing with exception path packets which need > to be injected into the > +Linux kernel for processing there. > +In this regard, virtio-user and vhost in kernel space are an alternative > to DPDK KNI for > +transferring packets between a DPDK packet processing application and the > kernel stack. > + > +This solution has a number of advantages over alternatives such as KNI: > > * Maintenance > > All kernel modules needed by this solution, vhost and vhost-net > (kernel), > - are upstreamed and extensively used kernel module. > + are upstreamed and extensively used. > > * Features > > - vhost-net is born to be a networking solution, which has lots of > networking > - related features, like multi queue, tso, multi-seg mbuf, etc. > + vhost-net is designed to be a networking solution, and, as such, has > lots of networking > + related features, such as multi queue support, TSO, multi-segment > buffer support, etc. > > * Performance > > - similar to KNI, this solution would use one or more kthreads to > - send/receive packets to/from user space DPDK applications, which has > little > - impact on user space polling thread (except that it might enter into > kernel > - space to wake up those kthreads if necessary). > + similar to KNI, this solution would uses one or more kthreads to > + send/receive packets to/from user space DPDK applications, which > minimises the impact > + on the polling DPDK threads. > > -The overview of an application using virtio-user as exceptional path is > shown > +The overview of an application using virtio-user as exception path is > shown > in :numref:`figure_virtio_user_as_exceptional_path`. > > .. _figure_virtio_user_as_exceptional_path: > > .. figure:: img/virtio_user_as_exceptional_path.* > > - Overview of a DPDK app using virtio-user as exceptional path > + Overview of a DPDK app using virtio-user as exception path > + > > +Example Usage With Testpmd > +--------------------------- > > -Sample Usage > ------------- > +.. note:: > + > + These instruction assume that the vhost/vhost-net kernel modules are > available and have already > + been loaded into the running kernel. > + It also assumes that the DPDK virtio driver has not been disabled in > the DPDK build. > > -As a prerequisite, the vhost/vhost-net kernel CONFIG should be chosen > before > -compiling the kernel and those kernel modules should be inserted. > +To run a simple test of virtio-user as exception path using testpmd: > > -#. Compile DPDK and bind a physical NIC to igb_uio/uio_pci_generic/vfio- > pci. > +#. Compile DPDK and bind a NIC to vfio-pci as documented > in :ref:`linux_gsg_linux_drivers`. > > - This physical NIC is for communicating with outside. > + This physical NIC is for communicating with the outside world, > + and serves as a packet source in this example. > > -#. Run testpmd. > +#. Run testpmd to forward packets from NIC to kernel, > + passing in a suitable list of logical cores to run on (``- > l``.parameter), This '.' should be a space? Overall, the changes LGTM. Thanks! Chenbo > + and optionally the PCI address of the physical NIC to use (``-a`` > parameter). > + The virtio-user device for interfacing to the kernel is specified via > a ``-vdev`` argument, > + taking the parameters described below. > > .. code-block:: console > > - $(testpmd) -l 2-3 -n 4 \ > - --vdev=virtio_user0,path=/dev/vhost-net,queue_size=1024 \ > - -- -i --tx-offloads=0x0000002c --enable-lro \ > - --txd=1024 --rxd=1024 > + /path/to/dpdk-testpmd -l <cores> -a <pci BDF> \ > + --vdev=virtio_user0,path=/dev/vhost- > net,queues=1,queue_size=1024 > > - This command runs testpmd with two ports, one physical NIC to > communicate > - with outside, and one virtio-user to communicate with kernel. > + * ``path`` > > -* ``--enable-lro`` > + The path to the kernel vhost-net device. > > - This is used to negotiate VIRTIO_NET_F_GUEST_TSO4 and > - VIRTIO_NET_F_GUEST_TSO6 feature so that large packets from kernel can > be > - transmitted to DPDK application and further TSOed by physical NIC. > + * ``queue_size`` > > -* ``queue_size`` > + 256 by default. To avoid shortage of descriptors, we can increase > it to 1024. > > - 256 by default. To avoid shortage of descriptors, we can increase it > to 1024. > + * ``queues`` > > -* ``queues`` > + Number of virt-queues. Each queue will be served by a kthread. > > - Number of multi-queues. Each queue will be served by a kthread. For > example: > +#. Once testpmd is running, a new network interface - called ``tap0`` by > default - > + will be present on the system. > + This should be configured with an IP address and then enabled for use: > > .. code-block:: console > > - $(testpmd) -l 2-3 -n 4 \ > - --vdev=virtio_user0,path=/dev/vhost- > net,queues=2,queue_size=1024 \ > - -- -i --tx-offloads=0x0000002c --enable-lro \ > - --txq=2 --rxq=2 --txd=1024 --rxd=1024 > + ip addr add 192.168.1.1/24 dev tap0 > + ip link set dev tap0 up > > -#. Enable Rx checksum offloads in testpmd: > +#. To observe packet forwarding through the kernel, > + a second testpmd instance can be run on the system, > + taking packets from the kernel using an ``af_packet`` socket on the > ``tap0`` interface. > > - .. code-block:: console > + .. code-block:: console > > - (testpmd) port stop 0 > - (testpmd) port config 0 rx_offload tcp_cksum on > - (testpmd) port config 0 rx_offload udp_cksum on > - (testpmd) port start 0 > + /path/to/dpdk-testpmd -l <cores> --vdev=net_af_packet0,iface=tap0 > --in-memory --no-pci > > -#. Start testpmd: > + When running this instance, > + we can use ``--in-memory`` flag to avoid hugepage naming conflicts > with the previous instance, > + and we also use ``--no-pci`` flag to only use the ``af_packet`` > interface for all traffic forwarding. > > - .. code-block:: console > +#. Running traffic into the system through the NIC should see that > traffic returned back again, > + having been forwarded through both testpmd instances. > + This can be confirmed by checking the testpmd statistics on testpmd > exit. > > - (testpmd) start > +For more advanced use of virtio-user with testpmd in this scenario, > +some other more advanced options may also be used. > +For example: > > -#. Configure IP address and start tap: > +* ``--tx-offloads=0x02c`` > + > + This testpmd option enables TX offloads for UDP and TCP checksum on > transmit, > + as well as TCP TSO support. > + The list of the offload flag values can be seen in header > `rte_ethdev.h > + <https://doc.dpdk.org/api/rte__ethdev_8h.html>`_. > + > +* ``--enable-lro`` > + > + This testpmd option is used to negotiate VIRTIO_NET_F_GUEST_TSO4 and > + VIRTIO_NET_F_GUEST_TSO6 feature so that large packets from the kernel > can be > + transmitted to the DPDK application and further TSOed by physical NIC. > + If unsupported by the physical NIC, errors may be reported by testpmd > with this option. > + > + > +* Enabling Rx checksum offloads for physical port: > + > + Within testpmd, you can enable and disable offloads on a per-port > basis, > + rather than enabling them for both ports. > + For the physical NIC, it may be desirable to enable checksum offload > on packet RX. > + This may be done as below, if testpmd is run with ``-i`` flag for > interactive mode. > > .. code-block:: console > > - ifconfig tap0 1.1.1.1/24 up > + testpmd> port stop 0 > + testpmd> port config 0 rx_offload tcp_cksum on > + testpmd> port config 0 rx_offload udp_cksum on > + testpmd> port start 0 > > -.. note:: > +* Multiple queue support > > - The tap device will be named tap0, tap1, etc, by kernel. > + Better performance may be achieved by using multiple queues, > + so that multiple kernel threads are handling the traffic on the > kernel side. > + For example, to use 2 queues on both NIC and virtio ports, > + while also enabling TX offloads and LRO support: > > -Then, all traffic from physical NIC can be forwarded into kernel stack, > and all > -traffic on the tap0 can be sent out from physical NIC. > + .. code-block:: console > > -Limitations > ------------ > + /path/to/dpdk-testpmd --vdev=virtio_user0,path=/dev/vhost- > net,queues=2,queue_size=1024 -- \ > + -i --tx-offloads=0x002c --enable-lro --txq=2 --rxq=2 -- > txd=1024 --rxd=1024 > > -This solution is only available on Linux systems. > -- > 2.34.1
On Mon, May 30, 2022 at 06:33:14AM +0100, Xia, Chenbo wrote: > Hi Bruce, > > > -----Original Message----- > > From: Richardson, Bruce <bruce.richardson@intel.com> > > Sent: Saturday, May 28, 2022 12:37 AM > > To: dev@dpdk.org > > Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; Xia, Chenbo > > <chenbo.xia@intel.com>; Richardson, Bruce <bruce.richardson@intel.com> > > Subject: [PATCH v2 1/2] doc/howto: rework section on virtio-user as > > exception path > > > > This patch extensively reworks the howto guide on using virtio-user for > > exception packets. Changes include: > > > > * rename "exceptional path" to "exception path" > > * remove references to uio and just reference vfio-pci > > * simplify testpmd command-lines, giving a basic usage example first > > before adding on detail about checksum or TSO parameters > > * give a complete working example showing traffic flowing through the > > whole system from a testpmd loopback using the created TAP netdev > > * replace use of "ifconfig" with Linux standard "ip" command > > * other general rewording. > > > > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com> > > > > --- > > v2: fix checkpatch warnings > > --- > > .../howto/virtio_user_as_exceptional_path.rst | 159 +++++++++++------- > > I agree with the renaming. And should we rename this file, and if possible, the > attached img too. > I wasn't sure of the value of doing such a rename - afraid it might clobber up the git history. I'll add it as a separate patch in a v3. > > 1 file changed, 100 insertions(+), 59 deletions(-) > > > > diff --git a/doc/guides/howto/virtio_user_as_exceptional_path.rst > > b/doc/guides/howto/virtio_user_as_exceptional_path.rst > > index ec021af399..100376c32d 100644 > > --- a/doc/guides/howto/virtio_user_as_exceptional_path.rst > > +++ b/doc/guides/howto/virtio_user_as_exceptional_path.rst > > @@ -3,116 +3,157 @@ > > > > .. _virtio_user_as_exceptional_path: > > > > -Virtio_user as Exceptional Path > > -=============================== > > +Virtio_user as Exception Path > > +============================= > > > > -The virtual device, virtio-user, was originally introduced with vhost- > > user > > -backend, as a high performance solution for IPC (Inter-Process > > Communication) > > +.. note:: > > + > > + This solution is only applicable to Linux systems. > > + > > +The virtual device, virtio-user, was originally introduced with the > > vhost-user > > +backend as a high performance solution for IPC (Inter-Process > > Communication) > > and user space container networking. > > > > -Virtio_user with vhost-kernel backend is a solution for exceptional path, > > -such as KNI which exchanges packets with kernel networking stack. This > > -solution is very promising in: > > +Beyond this originally intended use, virtio-user can be used in > > conjunction with the vhost-kernel > > +backend as a solution for dealing with exception path packets which need > > to be injected into the > > +Linux kernel for processing there. > > +In this regard, virtio-user and vhost in kernel space are an alternative > > to DPDK KNI for > > +transferring packets between a DPDK packet processing application and the > > kernel stack. > > + > > +This solution has a number of advantages over alternatives such as KNI: > > > > * Maintenance > > > > All kernel modules needed by this solution, vhost and vhost-net > > (kernel), > > - are upstreamed and extensively used kernel module. > > + are upstreamed and extensively used. > > > > * Features > > > > - vhost-net is born to be a networking solution, which has lots of > > networking > > - related features, like multi queue, tso, multi-seg mbuf, etc. > > + vhost-net is designed to be a networking solution, and, as such, has > > lots of networking > > + related features, such as multi queue support, TSO, multi-segment > > buffer support, etc. > > > > * Performance > > > > - similar to KNI, this solution would use one or more kthreads to > > - send/receive packets to/from user space DPDK applications, which has > > little > > - impact on user space polling thread (except that it might enter into > > kernel > > - space to wake up those kthreads if necessary). > > + similar to KNI, this solution would uses one or more kthreads to > > + send/receive packets to/from user space DPDK applications, which > > minimises the impact > > + on the polling DPDK threads. > > > > -The overview of an application using virtio-user as exceptional path is > > shown > > +The overview of an application using virtio-user as exception path is > > shown > > in :numref:`figure_virtio_user_as_exceptional_path`. > > > > .. _figure_virtio_user_as_exceptional_path: > > > > .. figure:: img/virtio_user_as_exceptional_path.* > > > > - Overview of a DPDK app using virtio-user as exceptional path > > + Overview of a DPDK app using virtio-user as exception path > > + > > > > +Example Usage With Testpmd > > +--------------------------- > > > > -Sample Usage > > ------------- > > +.. note:: > > + > > + These instruction assume that the vhost/vhost-net kernel modules are > > available and have already > > + been loaded into the running kernel. > > + It also assumes that the DPDK virtio driver has not been disabled in > > the DPDK build. > > > > -As a prerequisite, the vhost/vhost-net kernel CONFIG should be chosen > > before > > -compiling the kernel and those kernel modules should be inserted. > > +To run a simple test of virtio-user as exception path using testpmd: > > > > -#. Compile DPDK and bind a physical NIC to igb_uio/uio_pci_generic/vfio- > > pci. > > +#. Compile DPDK and bind a NIC to vfio-pci as documented > > in :ref:`linux_gsg_linux_drivers`. > > > > - This physical NIC is for communicating with outside. > > + This physical NIC is for communicating with the outside world, > > + and serves as a packet source in this example. > > > > -#. Run testpmd. > > +#. Run testpmd to forward packets from NIC to kernel, > > + passing in a suitable list of logical cores to run on (``- > > l``.parameter), > > This '.' should be a space? > Thanks, good catch.
diff --git a/doc/guides/howto/virtio_user_as_exceptional_path.rst b/doc/guides/howto/virtio_user_as_exceptional_path.rst index ec021af399..100376c32d 100644 --- a/doc/guides/howto/virtio_user_as_exceptional_path.rst +++ b/doc/guides/howto/virtio_user_as_exceptional_path.rst @@ -3,116 +3,157 @@ .. _virtio_user_as_exceptional_path: -Virtio_user as Exceptional Path -=============================== +Virtio_user as Exception Path +============================= -The virtual device, virtio-user, was originally introduced with vhost-user -backend, as a high performance solution for IPC (Inter-Process Communication) +.. note:: + + This solution is only applicable to Linux systems. + +The virtual device, virtio-user, was originally introduced with the vhost-user +backend as a high performance solution for IPC (Inter-Process Communication) and user space container networking. -Virtio_user with vhost-kernel backend is a solution for exceptional path, -such as KNI which exchanges packets with kernel networking stack. This -solution is very promising in: +Beyond this originally intended use, virtio-user can be used in conjunction with the vhost-kernel +backend as a solution for dealing with exception path packets which need to be injected into the +Linux kernel for processing there. +In this regard, virtio-user and vhost in kernel space are an alternative to DPDK KNI for +transferring packets between a DPDK packet processing application and the kernel stack. + +This solution has a number of advantages over alternatives such as KNI: * Maintenance All kernel modules needed by this solution, vhost and vhost-net (kernel), - are upstreamed and extensively used kernel module. + are upstreamed and extensively used. * Features - vhost-net is born to be a networking solution, which has lots of networking - related features, like multi queue, tso, multi-seg mbuf, etc. + vhost-net is designed to be a networking solution, and, as such, has lots of networking + related features, such as multi queue support, TSO, multi-segment buffer support, etc. * Performance - similar to KNI, this solution would use one or more kthreads to - send/receive packets to/from user space DPDK applications, which has little - impact on user space polling thread (except that it might enter into kernel - space to wake up those kthreads if necessary). + similar to KNI, this solution would uses one or more kthreads to + send/receive packets to/from user space DPDK applications, which minimises the impact + on the polling DPDK threads. -The overview of an application using virtio-user as exceptional path is shown +The overview of an application using virtio-user as exception path is shown in :numref:`figure_virtio_user_as_exceptional_path`. .. _figure_virtio_user_as_exceptional_path: .. figure:: img/virtio_user_as_exceptional_path.* - Overview of a DPDK app using virtio-user as exceptional path + Overview of a DPDK app using virtio-user as exception path + +Example Usage With Testpmd +--------------------------- -Sample Usage ------------- +.. note:: + + These instruction assume that the vhost/vhost-net kernel modules are available and have already + been loaded into the running kernel. + It also assumes that the DPDK virtio driver has not been disabled in the DPDK build. -As a prerequisite, the vhost/vhost-net kernel CONFIG should be chosen before -compiling the kernel and those kernel modules should be inserted. +To run a simple test of virtio-user as exception path using testpmd: -#. Compile DPDK and bind a physical NIC to igb_uio/uio_pci_generic/vfio-pci. +#. Compile DPDK and bind a NIC to vfio-pci as documented in :ref:`linux_gsg_linux_drivers`. - This physical NIC is for communicating with outside. + This physical NIC is for communicating with the outside world, + and serves as a packet source in this example. -#. Run testpmd. +#. Run testpmd to forward packets from NIC to kernel, + passing in a suitable list of logical cores to run on (``-l``.parameter), + and optionally the PCI address of the physical NIC to use (``-a`` parameter). + The virtio-user device for interfacing to the kernel is specified via a ``-vdev`` argument, + taking the parameters described below. .. code-block:: console - $(testpmd) -l 2-3 -n 4 \ - --vdev=virtio_user0,path=/dev/vhost-net,queue_size=1024 \ - -- -i --tx-offloads=0x0000002c --enable-lro \ - --txd=1024 --rxd=1024 + /path/to/dpdk-testpmd -l <cores> -a <pci BDF> \ + --vdev=virtio_user0,path=/dev/vhost-net,queues=1,queue_size=1024 - This command runs testpmd with two ports, one physical NIC to communicate - with outside, and one virtio-user to communicate with kernel. + * ``path`` -* ``--enable-lro`` + The path to the kernel vhost-net device. - This is used to negotiate VIRTIO_NET_F_GUEST_TSO4 and - VIRTIO_NET_F_GUEST_TSO6 feature so that large packets from kernel can be - transmitted to DPDK application and further TSOed by physical NIC. + * ``queue_size`` -* ``queue_size`` + 256 by default. To avoid shortage of descriptors, we can increase it to 1024. - 256 by default. To avoid shortage of descriptors, we can increase it to 1024. + * ``queues`` -* ``queues`` + Number of virt-queues. Each queue will be served by a kthread. - Number of multi-queues. Each queue will be served by a kthread. For example: +#. Once testpmd is running, a new network interface - called ``tap0`` by default - + will be present on the system. + This should be configured with an IP address and then enabled for use: .. code-block:: console - $(testpmd) -l 2-3 -n 4 \ - --vdev=virtio_user0,path=/dev/vhost-net,queues=2,queue_size=1024 \ - -- -i --tx-offloads=0x0000002c --enable-lro \ - --txq=2 --rxq=2 --txd=1024 --rxd=1024 + ip addr add 192.168.1.1/24 dev tap0 + ip link set dev tap0 up -#. Enable Rx checksum offloads in testpmd: +#. To observe packet forwarding through the kernel, + a second testpmd instance can be run on the system, + taking packets from the kernel using an ``af_packet`` socket on the ``tap0`` interface. - .. code-block:: console + .. code-block:: console - (testpmd) port stop 0 - (testpmd) port config 0 rx_offload tcp_cksum on - (testpmd) port config 0 rx_offload udp_cksum on - (testpmd) port start 0 + /path/to/dpdk-testpmd -l <cores> --vdev=net_af_packet0,iface=tap0 --in-memory --no-pci -#. Start testpmd: + When running this instance, + we can use ``--in-memory`` flag to avoid hugepage naming conflicts with the previous instance, + and we also use ``--no-pci`` flag to only use the ``af_packet`` interface for all traffic forwarding. - .. code-block:: console +#. Running traffic into the system through the NIC should see that traffic returned back again, + having been forwarded through both testpmd instances. + This can be confirmed by checking the testpmd statistics on testpmd exit. - (testpmd) start +For more advanced use of virtio-user with testpmd in this scenario, +some other more advanced options may also be used. +For example: -#. Configure IP address and start tap: +* ``--tx-offloads=0x02c`` + + This testpmd option enables TX offloads for UDP and TCP checksum on transmit, + as well as TCP TSO support. + The list of the offload flag values can be seen in header `rte_ethdev.h + <https://doc.dpdk.org/api/rte__ethdev_8h.html>`_. + +* ``--enable-lro`` + + This testpmd option is used to negotiate VIRTIO_NET_F_GUEST_TSO4 and + VIRTIO_NET_F_GUEST_TSO6 feature so that large packets from the kernel can be + transmitted to the DPDK application and further TSOed by physical NIC. + If unsupported by the physical NIC, errors may be reported by testpmd with this option. + + +* Enabling Rx checksum offloads for physical port: + + Within testpmd, you can enable and disable offloads on a per-port basis, + rather than enabling them for both ports. + For the physical NIC, it may be desirable to enable checksum offload on packet RX. + This may be done as below, if testpmd is run with ``-i`` flag for interactive mode. .. code-block:: console - ifconfig tap0 1.1.1.1/24 up + testpmd> port stop 0 + testpmd> port config 0 rx_offload tcp_cksum on + testpmd> port config 0 rx_offload udp_cksum on + testpmd> port start 0 -.. note:: +* Multiple queue support - The tap device will be named tap0, tap1, etc, by kernel. + Better performance may be achieved by using multiple queues, + so that multiple kernel threads are handling the traffic on the kernel side. + For example, to use 2 queues on both NIC and virtio ports, + while also enabling TX offloads and LRO support: -Then, all traffic from physical NIC can be forwarded into kernel stack, and all -traffic on the tap0 can be sent out from physical NIC. + .. code-block:: console -Limitations ------------ + /path/to/dpdk-testpmd --vdev=virtio_user0,path=/dev/vhost-net,queues=2,queue_size=1024 -- \ + -i --tx-offloads=0x002c --enable-lro --txq=2 --rxq=2 --txd=1024 --rxd=1024 -This solution is only available on Linux systems.
This patch extensively reworks the howto guide on using virtio-user for exception packets. Changes include: * rename "exceptional path" to "exception path" * remove references to uio and just reference vfio-pci * simplify testpmd command-lines, giving a basic usage example first before adding on detail about checksum or TSO parameters * give a complete working example showing traffic flowing through the whole system from a testpmd loopback using the created TAP netdev * replace use of "ifconfig" with Linux standard "ip" command * other general rewording. Signed-off-by: Bruce Richardson <bruce.richardson@intel.com> --- v2: fix checkpatch warnings --- .../howto/virtio_user_as_exceptional_path.rst | 159 +++++++++++------- 1 file changed, 100 insertions(+), 59 deletions(-) -- 2.34.1