path: root/doc/guides/nics
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authorCiara Loftus <>2019-09-30 16:42:05 +0000
committerFerruh Yigit <>2019-10-23 16:43:10 +0200
commitd8a210774e1d4c295fd93b983538da0d15312edd (patch)
tree38262366df84e140841b28359ce3f9d9ebe28d82 /doc/guides/nics
parent01b3156d33e06f829d1b1ae8302d4a53266f2864 (diff)
net/af_xdp: support unaligned umem chunks
This patch enables the unaligned chunks feature for AF_XDP which allows chunks to be placed at arbitrary places in the umem, as opposed to them being required to be aligned to 2k. This allows for DPDK application mempools to be mapped directly into the umem and in turn enable zero copy transfer between umem and the PMD. This patch replaces the zero copy via external mbuf mechanism introduced in commit e9ff8bb71943 ("net/af_xdp: enable zero copy by external mbuf"). The pmd_zero copy vdev argument is also removed as now the PMD will auto-detect presence of the unaligned chunks feature and enable it if so and otherwise fall back to copy mode if not detected. Signed-off-by: Ciara Loftus <> Signed-off-by: Kevin Laatz <> Reviewed-by: Xiaolong Ye <>
Diffstat (limited to 'doc/guides/nics')
1 files changed, 1 insertions, 1 deletions
diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
index ec46f08..b434b25 100644
--- a/doc/guides/nics/af_xdp.rst
+++ b/doc/guides/nics/af_xdp.rst
@@ -35,7 +35,6 @@ The following options can be provided to set up an af_xdp port in DPDK.
* ``iface`` - name of the Kernel interface to attach to (required);
* ``start_queue`` - starting netdev queue id (optional, default 0);
* ``queue_count`` - total netdev queue number (optional, default 1);
-* ``pmd_zero_copy`` - enable zero copy or not (optional, default 0);
@@ -48,6 +47,7 @@ This is a Linux-specific PMD, thus the following prerequisites apply:
<kernel src tree>/tools/lib/bpf;
* A Kernel bound interface to attach to;
* For need_wakeup feature, it requires kernel version later than v5.3-rc1;
+* For PMD zero copy, it requires kernel version later than v5.4-rc1;
Set up an af_xdp interface