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Diffstat (limited to 'Documentation/networking/ethtool-netlink.rst')
| -rw-r--r-- | Documentation/networking/ethtool-netlink.rst | 51 |
1 files changed, 35 insertions, 16 deletions
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst index e1bc6186d7ea..2540c70952ff 100644 --- a/Documentation/networking/ethtool-netlink.rst +++ b/Documentation/networking/ethtool-netlink.rst @@ -860,22 +860,24 @@ Request contents: Kernel response contents: - ==================================== ====== =========================== - ``ETHTOOL_A_RINGS_HEADER`` nested reply header - ``ETHTOOL_A_RINGS_RX_MAX`` u32 max size of RX ring - ``ETHTOOL_A_RINGS_RX_MINI_MAX`` u32 max size of RX mini ring - ``ETHTOOL_A_RINGS_RX_JUMBO_MAX`` u32 max size of RX jumbo ring - ``ETHTOOL_A_RINGS_TX_MAX`` u32 max size of TX ring - ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring - ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring - ``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_CQE_SIZE`` u32 Size of TX/RX CQE - ``ETHTOOL_A_RINGS_TX_PUSH`` u8 flag of TX Push mode - ``ETHTOOL_A_RINGS_RX_PUSH`` u8 flag of RX Push mode - ==================================== ====== =========================== + ======================================= ====== =========================== + ``ETHTOOL_A_RINGS_HEADER`` nested reply header + ``ETHTOOL_A_RINGS_RX_MAX`` u32 max size of RX ring + ``ETHTOOL_A_RINGS_RX_MINI_MAX`` u32 max size of RX mini ring + ``ETHTOOL_A_RINGS_RX_JUMBO_MAX`` u32 max size of RX jumbo ring + ``ETHTOOL_A_RINGS_TX_MAX`` u32 max size of TX ring + ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring + ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring + ``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_CQE_SIZE`` u32 Size of TX/RX CQE + ``ETHTOOL_A_RINGS_TX_PUSH`` u8 flag of TX Push mode + ``ETHTOOL_A_RINGS_RX_PUSH`` u8 flag of RX Push mode + ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` u32 size of TX push buffer + ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX`` u32 max size of TX push buffer + ======================================= ====== =========================== ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` indicates whether the device is usable with page-flipping TCP zero-copy receive (``getsockopt(TCP_ZEROCOPY_RECEIVE)``). @@ -891,6 +893,18 @@ through MMIO writes, thus reducing the latency. However, enabling this feature may increase the CPU cost. Drivers may enforce additional per-packet eligibility checks (e.g. on packet size). +``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` specifies the maximum number of bytes of a +transmitted packet a driver can push directly to the underlying device +('push' mode). Pushing some of the payload bytes to the device has the +advantages of reducing latency for small packets by avoiding DMA mapping (same +as ``ETHTOOL_A_RINGS_TX_PUSH`` parameter) as well as allowing the underlying +device to process packet headers ahead of fetching its payload. +This can help the device to make fast actions based on the packet's headers. +This is similar to the "tx-copybreak" parameter, which copies the packet to a +preallocated DMA memory area instead of mapping new memory. However, +tx-push-buff parameter copies the packet directly to the device to allow the +device to take faster actions on the packet. + RINGS_SET ========= @@ -908,6 +922,7 @@ Request contents: ``ETHTOOL_A_RINGS_CQE_SIZE`` u32 Size of TX/RX CQE ``ETHTOOL_A_RINGS_TX_PUSH`` u8 flag of TX Push mode ``ETHTOOL_A_RINGS_RX_PUSH`` u8 flag of RX Push mode + ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` u32 size of TX push buffer ==================================== ====== =========================== Kernel checks that requested ring sizes do not exceed limits reported by @@ -1084,6 +1099,10 @@ such that the corresponding bit in ``ethtool_ops::supported_coalesce_params`` is not set), regardless of their values. Driver may impose additional constraints on coalescing parameters and their values. +Compared to requests issued via the ``ioctl()`` netlink version of this request +will try harder to make sure that values specified by the user have been applied +and may call the driver twice. + PAUSE_GET ========= |