Xdp redirect performance XDP_DROP performance okay, but AFAICR it was also okay before, as it was only affected by DMA-sync call. You switched accounts on another tab or window. due to a full queue), it is necessary to free it by calling xdp_return_frame_rx_napi. XDP actions. Hey Folks, this time I will talk about a pretty awesome feature in the Linux kernel: AF_XDP. To gain performance XDP_REDIRECT does RX-bulking towards destinations, which unfortunately Hybrid XDP in TAP (since 4. Usage of reproducer. In my case I want to redirect Using the XDP_REDIRECT action from an XDP program, the program can redirect ingress frames to other XDP enabled netdevs, using the bpf_redirect_map() function. Heads-up XDP performance nerds! I got an unpleasant surprise when I updated my GCC compiler (to support the option -mindirect-branch=thunk-extern). I was happy to find XDP for my auto mod needs as they offered lower prices compared other competitors on the products I was wanting to buy. One step further in that direction is XDP, which was recently merged into the Linux kernel and allows for DPDK-like performance for the kernel itself. chan@broadcom. org, Vladimir Olovyannikov <vladimir. DPDK and XDP have some overlap in function around used for high-performance packet processing in network applications, however their mode of operation and capabilities are quite different. An AF_XDP socket in user space can addition- The patchset uses mlx5 as the sample driver, which gets implemented XDP_REDIRECT RX-mode, but not ndo_xdp_xmit (as this API is subject to change thought the patchset). While improvements have been measurable in several areas, a new wave of architecture-related security issues and related counter-measures has undone most of the gains, and purely i XDP_REDIRECT — Bypasses the normal network stack and redirects the packet via another NIC to the network. Nick made sure I received my 5% military discount on my purchase. A new struct xdp_frame is introduced (modeled after cpumap xdp_pkt). Program calls bpf_redirect_map(), returning XDP_REDIRECT. In our use case we will focus on the XDP_REDIRECT. XDP is short for eXpressed Data Path (it is merged in kernel 4. g. This powerful technology enables high-performance packet processing, offering unparalleled speed XDP_REDIRECT: It allows a packet to bypass the usual path it would take through the Linux kernel’s networking stack, AF_XDP is an address family that is optimized for high performance packet processing. An AF_XDP socket (XSK) is created with the normal socket() syscall. extend BPF – Evolution from classical BPF, assembly-like, interpreter – Effective: more registers and instructions, larger stack – Read or write access to context (packets for net) – LLVM backend – safety: in kernel verifier XDP_REDIRECT is similar to XDP_TX in that it is able to transmit the XDP packet, but through another NIC. I cannot understand what cause this speed performance to go down. The catch then, is any synchronization needs to be handled Note: You can keep a count of the number of times your program redirects a packet by running: sudo bpftrace -e 'tracepoint:xdp:xdp_redirect { @cnt[probe] = count(); }' Note : You can dump the raw packets being processed by the XDP program (similar to tcpdump ) You will need a kernel that supports XDP and, for the most performance improvement, a network card that support XDP in the driver. The component will be maintained in bpftime repo later, and we are trying to make it better!. Please keep in mind, that this is a summary and explanation in my own words, and it’s not intended to fully cover all technical depths. net>, bpfman's Integration with the AF_XDP Device Plugin and CNI for Kubernetes. It aims to create hooks as early as possible in the RX path (usally in the NIC driver), making packet processing in the Linux kernel much faster, as it is further illustrated in this paper. Or any other technology that is hopefully that fast. Dropping all packets is as fast as redirecting all packets with xdp_redirect_map: ~11Mpps. Skip to main content Products. It's not for production usage. XDP_REDIRECT on TCP traffic between veth devices is just going to be slower @tohojo I'm running a experiment compare the performance of xdp and the linux bridge in linux 6. AF_XDP standard (DT) coupled with Generic XDP suffers the performance degradation of R XDP is a programmable and high performance networking data path. For more information on these maps, please see the specific map documentation. • XDP_REDIRECT Transmit the packet from another interface. It is intended to be a simple program demonstrating the various operating modes; these include dropping packets, hairpin forwarding (using the XDP_TX return code), and redirection using the various in-kernel Using the XDP_REDIRECT action from an XDP program, the program can: redirect ingress frames to other XDP enabled netdevs if the driver has support for XDP, it will be used by the AF_XDP: code to provide better performance, but there is still a copy of the: data into user space. The core returned must be a like-for I will go over what XDP is, how to build an XDP packet forwarder combined with a BGP router, and of course, look at the performance. In the world of high-performance networking, while the AF-XDP redirects it to the XDP socket on the opposite end, attached to the user-space program. Nick sent me an order with breakdown of costs prior to my purchase. the redirected packets are sent to UDP server in the container via the container's eXpress Data Path provides a high performance, programmable network data path in the Linux kernel. From: Greg Kroah-Hartman <gregkh@linuxfoundation. You signed out in another tab or window. Here, an explicit redirect type is added to bpf_redirect_info, Saved searches Use saved searches to filter your results more quickly Nick at XDP was friendly and helpful. TODO Feature: cpumap could use netif_receive_skb_list From: Björn Töpel <bjorn. Today, the redirect targets for XDP either uses a map, or is based on ifindex. com>, Michael Chan <michael. Apparently it has to be done as fast as possible, I have found that by using eBFP and XDP, I can capture packets with high performance, but as far as I can see XDP verdicts are either abort, drop, pass, and tx. Process¶ XDP_REDIRECT works by a three-step Introduction XDP (eXpress Data Path) is a framework for fast packet processing in the Linux kernel. org. This approach significantly XDP (eXpress Data Path) is a powerful new networking feature in Linux that enables high-performance programmable access to networking packets before they enter the networking stack. AF_XDP sockets enable the possibility for XDP programs to redirect frames to a memory buffer in a user-space application. Packet Processing with XDP Bypasses skb allocations and host networking stack (e. What is XDP? XDP is an extended Berkeley Packet Filter (eBPF) based high-performance data path XDP_REDIRECT The redirect action allows a BPF program to redirect the packet somewhere else, either a different CPU or different NIC. 1. I've identified the issue, which is caused by This makes XDP_REDIRECT a versatile action for efficient network traffic management and redirection. The Assignment 4 I am trying to use xdp to redirect network traffic between VM taps. DETAILED DESCRIPTION . The official kernel This page documents the 'bpf_redirect' eBPF helper function, including its definition, usage, program types that can use it, and examples. Find and fix vulnerabilities Actions. It allows the processing of packets at the earliest stage in the kernel networking stack. Gener-ally, AF_XDP is used to accelerate packets’ processing or fastly forward packets to userspace [14,21,29]. XDP is eBPF + early packet processing 2). It provides bare metal packet processing at the lowest point in the Redirecting packets, using the XDP_TX (or XDP_REDIRECT) return code, can be used for implementing a load balancer. kernel. The focus lies on understanding AF_XDP’s core concepts, learn how to use it, and what to consider while using it. Except for XDP, both ingress and egress interfaces can be used for redirection. olovyannikov@broadcom. This process is illustrated in Figure 1. XDP-bench is a benchmarking utility for exercising the different operation modes of XDP. So this was discussed on IRC (#xdp, Freenode) and the xdp-newbies mailing list. sh XDP is a high performance data path in the Linux kernel based on the eBPF runtime (extended Berkeley Packet Filter). gz Atom feed top 2024-09-21 16:52 [RFC bpf-next 0/4] Add XDP rx hw hints support performing XDP_REDIRECT Lorenzo Bianconi 2024-09-21 16:52 ` [RFC bpf-next 1/4] net: xdp: Add xdp_rx_meta structure Lorenzo Bianconi 2024-09 Among the reasons that justify this increase in performance of REDIRECT_MAP against REDIRECT include implementation enhancements and changing method of forwarding packets. What I was expecting is that I can It is important to understand that XDP in-itself is not a kernel bypass facility. This is because the helper has no reference to the calling netdev, so unfortunately we can't do the ifindex lookup directly in the helper. This brings clear performance advantages for XDP_DROP and XDP_REDIRECT (VM does not need to be woken up to process packets at all). During the remanufacturing process each engine is carefully disassembled and machined using some of the most advanced equipment. XDP_REDIRECT is similar to XDP_TX in that it is able to transmit the XDP packet, but through another NIC. You could have several sockets receiving packets from one queue, but you cannot have, as of this writing, one socket receiving on more than one queue. Skip to content which provides increased performance. But XDP has a high. 13) tun_net_xmit TX skb array tun_recvmsg tun_sendmsg() Native XDP ndo_xdp_xmit() ethX build_skb() XDP_REDIRECT XDP_PAS XDP_TX S XDP_DROP Generic XDP helpers small packet Zerocopy or big packets Merged in 4. XDP ATTACH and bpf xsk redirect, attach at-most one socket per netdev queue, load built-in XDP program, 2-level hierarchy Remove indirect call, bpf prog run xdp Remove indirect call, XDP actions switch-statement (>= 5 =)jump table) Driver optimizations (batching, code restructure) bpf prog run xdp, xdp do redirect and xdp do flush map: per-CPU XDP: Recently introduced features Multibuf (Lozenzo, Maciej, Eelco) XDP hints on RX (Jesper, Stanislav, Toke) Feature flags (Lorenzo) More stack helpers (conntrack, synproxy) (Kartikeya, Lorenzo, Maxim) XDP_REDIRECT improvements Multicast (Hangbin) Map lookup, hashmap type, bpf_redirect() performance (Toke) Programs in devmap/cpumap (David When arrived packets are the UDP protocol and the destination port is 7999, the XDP program will redirects packets to a specific interface according to redirecting rules in the eBPF map. Transport layer XDP XDP operate at L2 (Eth) or L3 (IP) Tom Herbert (coined XDP) proposed = L4 (TCP/UDP) To gain performance it need to operate on xdp_frame’s For many fast-path TCP/UDP use-cases, SKB is pure overhead Much simpler xdp_frame will be sufficient Let special cases fall-through, alloc+init full SKB Transport-layer XDP XDP closer integration with An interesting feature that I implemented about a year ago (it first appeared in the 5. • Initial Performance Results • Next-steps for certain use-cases • Typical XDP use -case applications: Firewall, Load balancer, Traffic monitoring, etc. 3. 52 \(\upmu \) s, for a \(95\%\) confidence interval. Operation Performance is not as good since the packet has entered the network stack. 21. Improve XDP cpumap redirect example: flow hashing (fix NIC HW hash) Help get AF_XDP API and performance aligned; Help get AF_XDP zero-copy integrated via XDP return API; convert tracepoint to use ifindex instead of names (strcpy overhead) XDP_REDIRECT: Detect buggy-drivers forgetting to clear per-CPU map; Streamline eBPF map-create return You will need a kernel that supports XDP and, for the most performance improvement, a network card that support XDP in the driver. Since AF_XDP is performant and more compatible than DPDK, developers leverage AF_XDP to achieve higher performance in their applications. My XDP redirect performance numbers when cut in half; from approx 13Mpps to 6Mpps (single CPU core). com>, Ray Jui <ray. It operates at the lowest point Redirect¶ XDP_REDIRECT¶ Supported maps¶ XDP_REDIRECT works with the following map types: BPF_MAP_TYPE_DEVMAP. Redirect¶ XDP_REDIRECT¶ Supported maps¶ XDP_REDIRECT works with the following map types: BPF_MAP_TYPE_DEVMAP. 0 Mpps What is going on? Using redirect maps is a HUGE performance boost, why!? XDP action XDP_REDIRECT In the Linux kernel, the following vulnerability has been resolved: igc: avoid returning frame twice in XDP_REDIRECT When a frame can not be transmitted in XDP_REDIRECT (e. 13) tun_net_xmit TX skb array tun_recvmsg tun_sendmsg() Native XDP ndo_xdp_xmit() ethX build_skb() XDP_REDIRECT XDP_PAS XDP_TX S XDP_DROP Fortunately, for XDP and TC programs we can access the kernel routing table using the bpf_fib_lookup() helper and use this information to redirect packets. XDP_REDIRECT improvements Multicast (Hangbin) Map lookup, hashmap type, bpf_redirect() performance (Toke) Programs in devmap/cpumap (David Ahern, Lorenzo) Eliminating indirect calls (Björn) Live mode BPF_PROG_RUN (Toke) AF_XDP need_wakeup mode (Magnus and Maxim) Atomic replace and bpf_link attachment (Toke, Andrii) 2. 8+) 3). The following figure shows the flow of packets using a This eBPF program can also make modifications to the packet and decide what happens next (for example, continue kernel processing, drop the packet, or redirect it to another interface). Programs are injected and attached in the kernel, event-based. XDP_REDIRECT: Indicates that the packet should be redirected to another NIC for processing. The bpf Once the NIC is in that state, the connections will stall consistenly, even when the connections are tried directly on the external interface (redirects map is empty (this can be set by running bash reproducer. Docker container : a container is dedicated to receiving packets redirected by the XDP program. XDP is designed for maximum performance, which is why certain driver-level use-cases were not supported, like multi-buffer packets We likely have to change drivers RX-loop anyhow, as XDP_TX and XDP_REDIRECT will also need to "collect" all buffers before the packet can be forwarded. XDP_ABORTED: Unlike the previous examples, this return code should not be manually included within a functional program. However, this is the responsibility of the caller of What is AF_XDP Introduced in v4. 0-36-generic: iperf between two node. For more details on XDP and eBPF, take a look at the following posts: Achieving high-performance, low-latency networking with XDP Egress driver: implement ndo_xdp_xmit (and ndo_xdp_flush) Performance low without using a map for redirect (single CPU core numbers, ixgbe): Using helper: bpf_redirect = 7. 2. Finally, XDP_TX: Forwards the packet (which may have been modified) to the same network interface it was received. Only XDP_TX is way slower. XDP_REDIRECT: Bypassed the normal network stack and redirects the packet to another NIC on the network. 5 Mpps Using helper: bpf_redirect_map = 13. 1). BPF_MAP_TYPE_XSKMAP. 20. I got inspired by this tutorial and wanted to test redirecting packets between veths on kubernetes I used hard-coded IP and MAC address in the XDP, and used return bpf_redirect、XDP_TX、XDP_REDIRECT but none of them Performance is not as good since the packet has entered the network stack. For completeness this should be fixed, but there is also an opportunity for performance improvements. 2024 (English) Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits Student thesis Alternative title. XDPLua Overview. Also I noticed that even when inserting non-existing ifindex I do not receive XDP_ABORTED but always XDP I write a simple Program Like this: SEC("tc_redirect") int _egress_redirect(struct __sk_buff *skb){ return bpf_redirect(5,0); // redirect all egress packets to interface 5 the tc command provided here is used to load the program as a TC filter, not as a XDP program as the title and tags suggest. To boost performance, you can use offloaded XDP, which shifts the already small cost of each data packet XDP, eXpress Data Path, is a high-performance networking technology in the Linux kernel that allows for fast and efficient XDP_REDIRECT — Bypasses the normal network stack and redirects Using the XDP_REDIRECT action from an XDP program, the program can redirect ingress frames to other XDP enabled netdevs, using the bpf_redirect_map() function. XDP is an in-kernel fast-path, that operates on raw-frames “inline” before they reach the normal Linux Kernel network stack. AF_XDP is an address/socket family that is optimized for high performance packet processing. Automate any Hybrid XDP in TAP (since 4. Nick at XDP was friendly and helpful. As further explained in Sect. Contribute to withlin/xdp-redirect-lab development by creating an account on GitHub. You signed in with another tab or window. KTH, School of Electrical Engineering and Computer Science (EECS). Acceptance Policy: No leaking fluids, all fluids must be drained, and the core must be sealed in a plastic bag. Concepts ===== In order to use an AF_XDP socket, a number of XDP_REDIRECT: redirect the packet The Single Producer / Single Consumer rings are largely where the performance of AF_XDP comes from. topel@intel. The fate of packets is decided by action codes that your program returns: XDP_PASS: XDP_REDIRECT: redirect the packet to another NIC or user space socket via the AF_XDP address family; BCC. 4. Other XDP actions include XDP_PASS, XDP_TX, and XDP_REDIRECT. The UDP packets are sent with the same headers and packet size (less than 1500 bytes). Commented Mar 26, 2020 at 15:16. The basic idea is that XDP is tightly coupled with eBPF and hooks into a very early ingress path at the driver layer, where it operates with direct access to the packet's DMA buffer. XDP programs can signal a desired behaviour by returning. \n With the provided reproducer script, the issue can be reproduced by sending\ntraffic on an veth interface that gets redirected to the bnxt_en NIC and\nresponse traffic is received without even being redirected on the bnxt_en\ninterface. I tried using other methods, such as bpf_redirect() and map. Process¶ XDP_REDIRECT works by a three-step AF XDP to get it to the performance levels of user-space network driver packages such as DPDK. XDP (eXpress Data Path) XDP (eXpress Data Path) is an eBPF based high Other available values are XDP_DROP (does the same), XDP_TX (sends back the packet out of the interface that received it), XDP_REDIRECT (sends the packet out of another interface). jui@broadcom. It takes advantage of XDP (an in Kernel fastpath), which essentially runs an eBPF program as early as possible on a network driver's receive path, and redirects the packet to an AF_XDP socket. • XDP utilizes Linux kernel eBPF infrastructure that associates an eBPF program • XDP_TX: Tx the packet out • XDP_REDIRECT: Redirect the packet to another network device Linux eXpress Data Path (XDP)¶ The Intel® Linux Ethernet drivers’ Native node XDP offers a standardized Linux API to achieve low-overhead Ethernet Layer2 packet-processing (encoding, decoding, filtering, and so on) on industrial protocols like UADP ETH, ETherCAT, or Profinet-RT/IRT, without any prior knowledge of Intel® Ethernet Controller architecture. 4 , t his paper uses a combination of XDP_PASS and XDP_TX to both send priority traffic up to the XDP_REDIRECT: Redirect the packet to another NIC (network interface controller). org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation. Can you please tell me what conditions regarding the interface you need to fulfill in order for the return codes XDP_REDIRECT and XDP_TX to work correctly? For example, I change the destination port, and return the XDP_PASS code, the pac To gain performance XDP_REDIRECT does RX-bulking towards destinations, which unfortunately means that XDP-prog doesn’t get errors directly returned through the BPF-helper call bpf_redirect() (or bpf_redirect_map). The second header, which still is UPDATE: The performance slowdown is not only due checksum missing, it is also caused by the test-case that cause page_pool in mlx5 to run dry, The test setup with XDP-redirect into veth (that does XDP_PASS) is the same as described in . XDP is a framework used to write very high-speed packet processing in Fundamentally, XDP is moved out of the hardware-based VM with the assumption that a software VM is secure enough. Additionally, the program exports counters for the num-bers of SYN cookies issued on each port. 18 New ‘sinkhole’ for XDP_REDIRECT Offloads traffic to userspace Generic XDP No code needed Works for all drivers Small performance gains Native XDP Good performance gains on Rx Tx still goes through SKBs Zero-copy Significant performance gains Offloaded Tx path As of now, I would not mind to try and test anything outside mainline if I can get XDP_REDIRECT to work between Ethernet and WiFi. It can also modified the packet before the redirection. The eXpress Data Path (XDP) is a relatively new feature introduced to the Linux kernel in 2016. Helper sets per-cpu fields in struct bpf_redirect_info; Driver calls xdp_do_redirect() Converts xdp_buff to xdp_frame, For good forwarding performance, splitting work among CPUs is In AF_XDP standard (NN), received packets are redirected to the xsk via the XDP_REDIRECT action within the native XDP program, subsequently undergoing processing through the 8-bit quantized NN classifiers within the user space application. 5. I tried other redirect methods, such as XDP_TX and XDP_REDIRECT from veth2 to veth2 and they worked. (c) shows our proposed approach, loading the XDP program into kernel and processing the flows by implementing Hi, I am newbie to XDP. 1 "rebranded" Thanks to: Tom Herbert, Alexei and Brenden Blanco, putting effort behind idea Performance is primary focus and concern Target is competing with DPDK No fancy features! Need features: use normal stack delivery Using the XDP_REDIRECT action from an XDP program, the program can redirect ingress frames to other XDP enabled netdevs, using the bpf_redirect_map() function. I notice that when I load the xdp program, the network is much slower (130 Mbits/sec) from when I am loading the same code on the vmbr (4. Hello everybody, I'm new to the XDP world and have a question about redirecting to other interfaces in XDP. The\nissue is present when using the XDP helper functions bpf_redirect as well as\nbpf_redirect_map. 18 kernel), is the ability to make the BPF_PROG_RUN syscall run in a “live packet mode” for XDP. BPF_MAP_TYPE_CPUMAP. Process¶ XDP_REDIRECT works by a three-step Contribute to xdp-project/net-next development by creating an account on GitHub. The two functions bpf_redirect_map and bpf_redirect only takes one interface as an argument. Fig- XDP redirect to other netdevices RX path 1 XDP program per queue pair XDP support on TX Multi produce single consumer queues for AF_XDP Still lots of performance optimization and design work to be performed Lots of exciting XDP extensions possibile in conjunction with AF_XDP XDP_REDIRECT: Using the XDP_REDIRECT action from an XDP program, again this can cost performance. We’ll use this function later to build our router. Skip to content. The idea behind this feature is to add the possibility to define on which CPU run the eBPF program if You will need a kernel that supports XDP and, for the most performance improvement, a network card that support XDP in the driver. XDP, short for eXpress Data Path, has emerged as a game-changer in the Linux networking landscape. Write better code with AI Security. Using the XDP_REDIRECT action from an XDP program, the program can redirect ingress frames to other XDP enabled netdevs, using the bpf_redirect_map() function. Navigation Menu Toggle navigation. Contribute to alpha-li/linux-bpf-samples development by creating an account on GitHub. org> To: linux-kernel@vger. Instead these errors can be debugged via using the XDP tracepoint available in the kernel. XDP_REDIRECT: It allows a packet to bypass the usual path it would take through the Linux kernel's networking stack, AF_XDP is an address family that is optimized for high performance packet processing. Traffic mirroring, or a Switch Port Analyzer (SPAN ), The second facility is the eXpress Data Path (XDP). Load balancing –with XDP_REDIRECT, XDP will redirect packets to other NICs or user space If you also run XDP on a physical interface, and use XDP_REDIRECT to send frames into a veth device, they will be preserved in XDP frame form as they traverse through the veth; so if you run another XDP program on the other end of the veth pair, you can process the XDP frame directly, before the kernel builds an SKB out of it. Note! The code in this repo is a Research Prototype for experiment. And both ndo_xdp_xmit and the new xdp_return_frame end-up using this. This page documents the 'bpf_redirect_map' eBPF helper function, including its definition, usage, program types that can use it, and examples. Synopsis. bpf samples in linux kernel. The root-cause the realloc issue is that veth_xdp_rcv_skb() code path (that handles SKBs like generic-XDP) is calling a native-XDP function xdp_do_redirect(), instead of simply using xdp_do_generic_redirect() that can handle SKBs. To quantify the advantages of the XDP approach, we com-pared the performance of 100 TCP CRR-style flows while the host is subjected to SYN floods of various magnitudes. It acts as an early hook in the Linux network receive (RX) path that can be used to bypass the kernel network XDP_REDIRECT action). 1 I want to use XDP for redirecting packets sent from pint-1 to ping-3 pod redirect to ping-2 pod inside Kubernetes, and testing this using ICMP(ping) inside the pod. Reporting here for the record. XDP got new action code XDP_REDIRECT (that drivers must implement) In basic form: Redirecting RAW frames out another net_device/ifindex Egress driver: implement ndo_xdp_xmit (and ndo_xdp_flush) When it comes to building performant applications one way to optimize for network throughput is using XDP. 2. Having a network card with support for RSS symmetric hashing is a good point or you will have to use the XDP CPU redirect map feature. redirect_map() with the appropriate values but veth3 still receives nothing. Commented Aug 11 You will need a kernel that supports XDP and, for the most performance improvement, a network card that support XDP in the driver. It is essential, for the sake of performance, to avoid using per-packet allocations to convert the xdp_buff into an xdp_frame in order to allow queuing this object executing XDP_REDIRECT. 12 \(\upmu \) s, and the SREXT is 482. Background We have some devices sending unicast UDP packets which we want to receive on multiple computers by transforming those packets to broadcast. sh set_mode redirect_none). XDP (eXpress Data Path) XDP (eXpress Data Path) is an eBPF based high-performance data path merged in You will need a kernel that supports XDP and, for the most performance improvement, a network card that support XDP in the driver. xdp-bench - Man Page. One of the key concepts in this project is kernel scripting. One reason this is interesting is that it makes it possible to implement a programmable packet generator, that leverages the programmability and performance of XDP to achieve very 3/23 XDP – eXpress Data Path Introduction An eXpress Data Path (XDP) in kernel-space The "packet-page" idea from NetDev1. XDP_DROP: drops with XDP are fast, the buffers are just recycled to the rx ring queue; XDP_PASS: pass to the normal networking stack, possibly after modification Learn how XDP allows you to build network packet-processing programs with extremely high performance. gz Atom feed top 2024-09-21 16:52 [RFC bpf-next 0/4] Add XDP rx hw hints support performing XDP_REDIRECT Lorenzo Bianconi 2024-09-21 16:52 ` [RFC bpf-next 1/4] net: xdp: Add xdp_rx_meta structure Lorenzo Bianconi 2024-09 This means that with a bit of refactoring, we can finally fix the performance delta between the bpf_redirect_map() and bpf_redirect() helper functions, but drop packets on xdp_do_redirect(). Reload to refresh your session. 1 __builtin_memcpy(eth->h_dest, destination_mac , Thank you for your comment. TODO sample xdp_redirect_cpu should output interface-name and ifindex; DONE investigate sample xdp_redirect_cpu counters; TODO cpumap: This have already confused people. https: You will need a kernel that supports XDP and, for the most performance improvement, a network card that support XDP in the driver. We will go over what XDP is, how to build an XDP packet forwarder combined with a BGP router, and of course, look at the performance. Söderman, Felix . BPF_MAP_TYPE_DEVMAP_HASH. AF_XDP sockets XDP (eXpress Data Path) is a powerful new networking feature in Linux that enables high-performance programmable access to networking packets before they enter the networking stack. Performance Evaluation of AF_XDP and DPDK in Multi-Buffer Packet Processing Applications. The In our AF_XDP case, the redirecting (XDP_REDIRECT) is the most important action, because it allows to send packets directly to userspace. Userspace XDP is a novel system that allows eBPF XDP-based network functions (NFs) to execute in userspace, leveraging kernel bypassing techniques. Usage at ovn-bgp-agent. The existing code tries to steal the packet-data from the SKB (and frees the SKB itself). a simple XDP benchmarking tool. Miller" <davem@davemloft. XDP TX or XDP REDIRECT. , bridge) Can have a similar XDP program on the tap device to redirect to the egress NIC HOW the redirect decision is made is up to the ebpf program L2 / FDB lookup - tap into bridge fdb (need bpf helper) Using the XDP_REDIRECT action from an XDP program, the program can redirect ingress frames to other XDP enabled netdevs, using the bpf_redirect_map() function. Apart from the flexibility of updating maps from userspace, the redirect_map() helper also uses the map structure to batch packets, which results in a significant (around 50%) performance boost. Load balancing: AF_XDP sockets allow user-space applications to receive redirected The redirect mechanism will also perform bulking to increase performance: all packets in each NAPI polling period will be put into a bulking queue on the egress interface and released at Using the XDP_REDIRECT action from an XDP program, the program can redirect ingress frames to other XDP enabled netdevs, using the bpf_redirect_map() function. The BPF_F_INGRESS value in flags is used to make the distinction eBPF Generic, efficient, secure in-kernel (Linux) virtual machine. action code in addition to the existing XDP-REDIRECT or XDP-TX action codes. The fate of packets is decided by action codes that your program returns: XDP_PASS: XDP_REDIRECT: redirect the packet to another NIC or user space socket via the AF_XDP address family; BCC XDP ATTACH and bpf xsk redirect, attach at-most one socket per netdev queue, load built-in XDP program, 2-level hierarchy Remove indirect call, bpf prog run xdp Remove indirect call, XDP actions switch-statement (>= 5 =)jump table) Driver optimizations (batching, code restructure) bpf prog run xdp, xdp do redirect and xdp do flush map: per-CPU XDP_REDIRECT: redirect the packet to another NIC or user space socket via the AF_XDP address family; AF_XDP. org>, stable@vger. As the XDP program is executed in the driver, it can take these actions very quickly. XDP_REDIRECT – Bypasses the The latter scenario can be implemented using XDP_PASS or cpumap XDP_REDIRECT. XDP, formerly known as AF_PACKETv4 (which was never included in the mainline kernel), is a raw socket optimized for high performance packet processing and allows zero-copy between kernel and applications. Thus, the average processing time that the XDP approach with REDIRECT_MAP is 471. XDP stands for eXpress Data Path, and it allows for processing packets at the In past years, the kernel community has been using different approaches in the quest for ever-increasing networking performance. In this paper, we present various optimizations that fall into two (XDP TX) or another networking interface (XDP REDIRECT) as seen in Figure 1. – Qeole. com> The XDP_REDIRECT implementations for maps and non-maps are fairly similar, but obviously need to take different code paths depending on if the target is using a map or not. AF_XDP is an address family that is optimized for high performance packet processing. – Gef. The answer is that you did nothing wrong: With AF_XDP, a socket receives the packets from one hardware queue. TX sides similar: V4 xmit = XDP xmit + XDP flush XDP support with packet arrays even when zero-copy is not enabled – Buffers only allocated from the normal allocator in driver XDP_REDIRECT needs a destructor for V4 to work in zero-copy mode – Currently a copy is needed 20 int (*ndo_xdp)(struct net_device *dev, struct netdev_xdp *xdp); next prev parent reply other threads:[~2024-10-04 17:53 UTC|newest] Thread overview: 43+ messages / expand[flat|nested] mbox. We can't make any changes to the devices sending the packets nor the computers receiving the data. But XDP has a high learning Tracepoints are useful for debugging XDP, especially for XDP_REDIRECT. Generally, it is used to run networking and monitoring tools in Linux servers to ensure optimal performance. 13 − mix using native XDP and skb XDP − simplify the VM configuration (no notice from guest) ndo_start_xmit() An XDP program can redirect packets between interfaces using either the xdp_redirect() helper or the xdp_redirect_map() helper. To avoid any memory allocations, the xdp_frame object is placed in the top headroom of the data packet itself. 5 Gbits/sec). /mem/page_pool06_alloc_pages_bulk. com>, "David S. . next prev parent reply other threads:[~2024-10-04 17:53 UTC|newest] Thread overview: 45+ messages / expand[flat|nested] mbox. Sign in Product GitHub Copilot. Running XDP on dev:ixgbe2 (ifindex:9) XDP redirect (via devmap) RX:ixgbe2 -> TX:i40e1, this is redirect from RX link-speed 10Gbit/s out TXC 40Gbit/s link-speed to make sure TX side is not bottleneck. To support fast delivery of raw-frames into user space, XDP can bypass the Linux Kernel network stack via XDP_REDIRECT’ing into a special BPF-map containing With backgrounds in automotive, performance, and machining industries, the DFC technicians know the intimate workings of diesel engines. 4 AF_XDP Datapath To understand why AF_XDP can achieve better performance, we have to under- Flexibility in the data plane without sacrificing performance Specifically using XDP: easy way to perform some parts in kernel (heavy lifting) (special case of XDP_REDIRECT) Towards augmenting DNS software <- This work is about: adding functionality that is agnostic of DNS software running on the OS. 1 XDP use-case: Performance improvement of kernel network features XDP, eXpress Data Path [1, 2, 6], is a super-fast and flexible kernel using an XDP pro-gram to redirect packets to a userspace datapath running in ovs-vswitchd. XDP is not responsible for cores received damaged, freight penalties, and/or lost shipments. No, I did not enable SKB mode, in fact, I can even reproduce the issue by loading a minimal XDP program with just one line: return XDP_TX; which still results in ~4Mpps (can see the bandwith in bmon). Another option for the XDP_REDIRECT case is to redirect into a BPF cpumap, meaning, the CPUs serving XDP on the NIC’s receive queues can continue to do so and push the packet for processing the upper kernel stack to a remote CPU. Add a comment | Your Answer Similar to what David Ahern proposed in [1] for DEVMAPs, introduce the capability to attach and run a XDP program to CPUMAP entries. XDP is a programmable, high-performance packet processor in a Linux network data path. smqesh aeftxyl hnze hvnm xvtp crvibo kyyqju iztaur kxly ctt