From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 02E64530A for ; Tue, 25 Nov 2014 15:30:11 +0100 (CET) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 25 Nov 2014 06:40:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,455,1413270000"; d="scan'208";a="637815845" Received: from kmsmsx152.gar.corp.intel.com ([172.21.73.87]) by fmsmga002.fm.intel.com with ESMTP; 25 Nov 2014 06:40:23 -0800 Received: from shsmsx151.ccr.corp.intel.com (10.239.6.50) by KMSMSX152.gar.corp.intel.com (172.21.73.87) with Microsoft SMTP Server (TLS) id 14.3.195.1; Tue, 25 Nov 2014 22:40:23 +0800 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.216]) by SHSMSX151.ccr.corp.intel.com ([169.254.3.86]) with mapi id 14.03.0195.001; Tue, 25 Nov 2014 22:40:21 +0800 From: "Liang, Cunming" To: "Richardson, Bruce" , Neil Horman Thread-Topic: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated driver Thread-Index: AQHQCLnU9S2O+AEgcUegiDb9pmqkVZxw3yQAgAAB3oCAAIcloA== Date: Tue, 25 Nov 2014 14:40:20 +0000 Message-ID: References: <1416924682-24170-1-git-send-email-cunming.liang@intel.com> <20141125142316.GD23352@hmsreliant.think-freely.org> <20141125142956.GA6672@bricha3-MOBL3> In-Reply-To: <20141125142956.GA6672@bricha3-MOBL3> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated driver X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Nov 2014 14:30:13 -0000 > -----Original Message----- > From: Richardson, Bruce > Sent: Tuesday, November 25, 2014 10:30 PM > To: Neil Horman > Cc: Liang, Cunming; dev@dpdk.org > Subject: Re: [dpdk-dev] [RFC PATCH 0/6] DPDK support to bifurcated driver >=20 > 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"? > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D > > > > > > The "bifurcated driver" stands for the kernel NIC driver that support= s: > > > > > > 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 s= pace > > > > > > 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 > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > It's well accepted by industry to use DPDK to process fast path packe= ts in > > > user space in a high performance fashion, meanwhile processing slow p= ath > > > control packets in kernel space is still needed as those packets usua= lly > > > 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 D= PDK > > > software rings, at the cost of significant CPU cycles and memory > bandwidth. > > > > > > 2) Memory copy packets between kernel' socket buffer and mbuf bring= s > > > significant negative performance impact to KNI performance. > > > > > > The bifurcated driver provides a alternative approach that not only o= ffloads > > > 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 drive= r and > > > stack, and add other rules to distribute packets to the queues assign= ed 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 operat= ion > > > for high performance packet I/O. > > > > > > > > > What's the impact and change to DPDK > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > 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 use= r > space. > > > The bifurcated driver PMD talks to a NIC interface using raw socket A= PIs and > > > only mmap() limited I/O space (e.g. certain 4K pages) for accessing i= nvolved > > > 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 bifurcat= ed > netdev. > > > The socket fd will be used to request 'queue pairs info', > > > 'split/return queue pairs' and etc. The PCIe device ID, netdev MA= C > 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 devi= ce ID, > > > the correct driver should be used. And for such netdev device, th= e > creation > > > of PCIe device is no longer from scan but the on-demand assignmen= t. > > > > > > - 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 do= es. > > > > > > - 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 d= river > 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=3Drte_bifurc,iface=3Deth0,qpairs=3D1 -- \ > > > > -i --rxfreet=3D32 --txfreet=3D32 --txrst=3D32 > > > Note: > > > iface and qpairs arguments above specify the netdev interface nam= e and > > > number of qpairs that user space request from the "bifurcated dri= ver" > > > 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 hel= p 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 crea= ted 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=3Drte_bifurc= ' VDEV > > > from eal command-line. It generates the PCIe VDEV device ready for fu= rther > > > driver probe. It maintains the bifurcated device information include = sockfd, > > > hwaddr, mtu, qpairs, iface_name. It's used for other direct ring acce= ss 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 everyt= hing > > > from scratch. And it also modifies the rx/tx_queue_setup to allow que= ue > > > setup from any queue offset. > > > > > > Supported NIC driver > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D > > > > > > The "bifurcated driver" kernel patch only supports "ixgbe" driver at = the > moment, > > > so this RFC patch also provides "ixgbe" PMD via direct-mapped rings a= s > sample. > > > The support for 40GE(i40e) will be added in the future. > > > > > > In addition, for those multi-queues enabled NIC with flow director ca= pability > > > to do perform packet classification and distribution, there's no spec= ial > > > technical gap to provide bifurcated driver approach support. > > > > > > Limitation > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > By using "bifurcated driver", user space only takes over the DMA oper= ation. > > > 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 eth= tool. > > > > > > > > > Any questions, comments and feedback are welcome. > > > > > > > > > -END- > > > > > > Signed-off-by: Cunming Liang > > > Signed-off-by: Danny Zhou > > > > > > *** 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 wo= rk, as > > there may still be kernel side changes that the user space pmd will hav= e 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 take= n for > this driver because it's significantly different that any other HW driver= . [Liang, Cunming] Yes, as Bruce said, that's the major purpose. Another one is having this patch, people can run it together with kernel pa= tch. It helps to understand the benefit and raise comments per user experience. >=20 > /Bruce