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| author |   Jakub Kicinski <kuba@kernel.org> | 2022-01-27 10:42:59 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2022-01-28 14:43:47 +0000 |
| commit | 9690ae60429020f38e4aa2540c306f27eb021bc0 (patch) | |
| tree | 05901b52f36783cdd5b53e2327752792304dc575 /Documentation/networking/ethtool-netlink.rst | |
| parent | Merge branch 'ksz-switch-refclk' (diff) | |
| download | linux-dev-9690ae60429020f38e4aa2540c306f27eb021bc0.tar.xz linux-dev-9690ae60429020f38e4aa2540c306f27eb021bc0.zip | |
ethtool: add header/data split indication
For applications running on a mix of platforms it's useful
to have a clear indication whether host's NIC supports the
geometry requirements of TCP zero-copy. TCP zero-copy Rx
requires data to be neatly placed into memory pages.
Most NICs can't do that.
This patch is adding GET support only, since the NICs
I work with either always have the feature enabled or
enable it whenever MTU is set to jumbo. In other words
I don't need SET. But adding set should be trivial.
(The only note on SET is that we will likely want
the setting to be "sticky" and use 0 / `unknown`
to reset it back to driver default.)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking/ethtool-netlink.rst')
| -rw-r--r-- | Documentation/networking/ethtool-netlink.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst index 9d98e0511249..cae28af7a476 100644 --- a/Documentation/networking/ethtool-netlink.rst +++ b/Documentation/networking/ethtool-netlink.rst @@ -860,8 +860,16 @@ Kernel response contents: ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring ``ETHTOOL_A_RINGS_RX_BUF_LEN`` u32 size of buffers on the ring + ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` u8 TCP header / data split ==================================== ====== =========================== +``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` indicates whether the device is usable with +page-flipping TCP zero-copy receive (``getsockopt(TCP_ZEROCOPY_RECEIVE)``). +If enabled the device is configured to place frame headers and data into +separate buffers. The device configuration must make it possible to receive +full memory pages of data, for example because MTU is high enough or through +HW-GRO. + RINGS_SET ========= |