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Diffstat (limited to 'Documentation/networking/af_xdp.rst')
| -rw-r--r-- | Documentation/networking/af_xdp.rst | 48 |
1 files changed, 27 insertions, 21 deletions
diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst index dceeb0d763aa..50d92084a49c 100644 --- a/Documentation/networking/af_xdp.rst +++ b/Documentation/networking/af_xdp.rst @@ -209,13 +209,10 @@ Libbpf Libbpf is a helper library for eBPF and XDP that makes using these technologies a lot simpler. It also contains specific helper functions -in tools/lib/bpf/xsk.h for facilitating the use of AF_XDP. It -contains two types of functions: those that can be used to make the -setup of AF_XDP socket easier and ones that can be used in the data -plane to access the rings safely and quickly. To see an example on how -to use this API, please take a look at the sample application in -samples/bpf/xdpsock_usr.c which uses libbpf for both setup and data -plane operations. +in tools/testing/selftests/bpf/xsk.h for facilitating the use of +AF_XDP. It contains two types of functions: those that can be used to +make the setup of AF_XDP socket easier and ones that can be used in the +data plane to access the rings safely and quickly. We recommend that you use this library unless you have become a power user. It will make your program a lot simpler. @@ -372,9 +369,8 @@ needs to explicitly notify the kernel to send any packets put on the TX ring. This can be accomplished either by a poll() call, as in the RX path, or by calling sendto(). -An example of how to use this flag can be found in -samples/bpf/xdpsock_user.c. An example with the use of libbpf helpers -would look like this for the TX path: +An example with the use of libbpf helpers would look like this for the +TX path: .. code-block:: c @@ -442,6 +438,15 @@ is created by a privileged process and passed to a non-privileged one. Once the option is set, kernel will refuse attempts to bind that socket to a different interface. Updating the value requires CAP_NET_RAW. +XDP_MAX_TX_SKB_BUDGET setsockopt +-------------------------------- + +This setsockopt sets the maximum number of descriptors that can be handled +and passed to the driver at one send syscall. It is applied in the copy +mode to allow application to tune the per-socket maximum iteration for +better throughput and less frequency of send syscall. +Allowed range is [32, xs->tx->nentries]. + XDP_STATISTICS getsockopt ------------------------- @@ -549,12 +554,12 @@ later in this document. Usage ----- -In order to use AF_XDP sockets two parts are needed. The -user-space application and the XDP program. For a complete setup and -usage example, please refer to the sample application. The user-space -side is xdpsock_user.c and the XDP side is part of libbpf. +In order to use AF_XDP sockets two parts are needed. The user-space +application and the XDP program. For a complete setup and usage example, +please refer to the xdp-project at +https://github.com/xdp-project/bpf-examples/tree/main/AF_XDP-example. -The XDP code sample included in tools/lib/bpf/xsk.c is the following: +The XDP code sample is the following: .. code-block:: c @@ -752,11 +757,12 @@ to facilitate extending a zero-copy driver with multi-buffer support. Sample application ================== - -There is a xdpsock benchmarking/test application included that -demonstrates how to use AF_XDP sockets with private UMEMs. Say that -you would like your UDP traffic from port 4242 to end up in queue 16, -that we will enable AF_XDP on. Here, we use ethtool for this:: +There is a xdpsock benchmarking/test application that can be found at +https://github.com/xdp-project/bpf-examples/tree/main/AF_XDP-example +that demonstrates how to use AF_XDP sockets with private +UMEMs. Say that you would like your UDP traffic from port 4242 to end +up in queue 16, that we will enable AF_XDP on. Here, we use ethtool +for this:: ethtool -N p3p2 rx-flow-hash udp4 fn ethtool -N p3p2 flow-type udp4 src-port 4242 dst-port 4242 \ @@ -773,7 +779,7 @@ can be displayed with "-h", as usual. This sample application uses libbpf to make the setup and usage of AF_XDP simpler. If you want to know how the raw uapi of AF_XDP is really used to make something more advanced, take a look at the libbpf -code in tools/lib/bpf/xsk.[ch]. +code in tools/testing/selftests/bpf/xsk.[ch]. FAQ ======= |