xref: /dpdk/doc/guides/nics/null.rst (revision b583b9a1bb49e86aa0937d55415713282000c536)
1..  SPDX-License-Identifier: BSD-3-Clause
2    Copyright(c) 2020 Intel Corporation.
3
4NULL Poll Mode Driver
5=====================
6
7NULL PMD is a simple virtual driver mainly for testing. It always returns success for all packets for Rx/Tx.
8
9On Rx it returns requested number of empty packets (all zero). On Tx it just frees all sent packets.
10
11
12Usage
13-----
14
15.. code-block:: console
16
17   ./<build_dir>/app/dpdk-testpmd -l 0-3 -n 4 --vdev net_null0 --vdev net_null1 -- -i
18
19
20Runtime Configuration
21---------------------
22
23- ``copy`` [optional, default disabled]
24
25 It copies data of the packet before Rx/Tx. For Rx it uses another empty dummy mbuf for this.
26
27.. code-block:: console
28
29   ./<build_dir>/app/dpdk-testpmd -l 0-3 -n 4 --vdev "net_null0,copy=1" -- -i
30
31- ``size`` [optional, default=64 bytes]
32
33 Custom packet length value to use.r
34 If ``copy`` is enabled, this is the length of copy operation.
35
36.. code-block:: console
37
38   ./<build_dir>/app/dpdk-testpmd -l 0-3 -n 4 --vdev "net_null0,size=256" -- -i
39
40- ``no-rx`` [optional, default disabled]
41
42 Makes PMD more like ``/dev/null``. On Rx no packets received, on Tx all packets are freed.
43 This option can't co-exist with ``copy`` option.
44