The ethdev timesync API currently exposes Tx timestamps through a shared hardware register. This requires applications to serialize timestamped packets and does not allow correlation when multiple packets are in flight.
This RFC proposes an ethdev interface for hardware with independent Tx timestamp slots. The interface reports the supported timestamping mechanism, provides a port-global slot lifecycle, and lets applications poll each slot asynchronously after transmission. The proposal includes the following components: * Capability reporting for shared-register and per-packet timestamping. * Slot allocation, asynchronous timestamp retrieval, and slot release. * A dual-domain timestamp structure for adjusted PHC and raw hardware time. * Mbuf dynamic field and dynflag support for passing slot handles to Tx, with a helper that stamps a slot handle onto an mbuf. * Registration and process-local reset of the cached dynfield state. * An ice PMD implementation using the 64 per-port PHY timestamp slots. * A testpmd command to report the slot capabilities of a port. * Programmer-guide and NIC feature documentation. The legacy rte_eth_timesync_read_tx_timestamp() API remains available on devices using a shared timestamp register. Changes since v3: * Added an ice PMD implementation of the new slot ops. The ice PHY exposes 64 Tx timestamp slots per port, which are now tracked in an atomic per-adapter bitmap instead of the single static slot the driver used before. On E822 the 64 quad slots are split evenly between the PFs sharing the quad so allocations never overlap. * The ice Tx context descriptor now takes the timestamp index from the mbuf dynamic field when the packet carries the slot dynflag, and falls back to the legacy static index otherwise. * The ice legacy single-slot read path now uses ptp_tx_index instead of a hardcoded slot 0, and clears the PHY timestamp on E810 after a read or a timeout so a stale entry cannot block later requests. * Added a testpmd command, "show port <port_id> tx_timestamp_caps", that reports the slot capabilities of a port and performs an allocate and release round-trip to exercise the API. Comments and suggestions on the interface and the ice implementation are welcome. Rajesh Kumar (3): ethdev: add Tx timestamp slot management APIs net/ice: support per-packet Tx timestamp slots app/testpmd: add Tx timestamp capabilities command app/test-pmd/cmdline.c | 79 ++++++ doc/guides/nics/features.rst | 16 +- doc/guides/prog_guide/ethdev/index.rst | 1 + doc/guides/prog_guide/ethdev/timesync.rst | 223 +++++++++++++++++ doc/guides/rel_notes/release_26_11.rst | 7 + drivers/net/intel/ice/ice_ethdev.c | 210 +++++++++++++++- drivers/net/intel/ice/ice_ethdev.h | 2 + drivers/net/intel/ice/ice_rxtx.c | 11 +- lib/ethdev/ethdev_driver.h | 25 ++ lib/ethdev/rte_ethdev.c | 202 ++++++++++++++++ lib/ethdev/rte_ethdev.h | 278 ++++++++++++++++++++++ 11 files changed, 1047 insertions(+), 7 deletions(-) create mode 100644 doc/guides/prog_guide/ethdev/timesync.rst -- 2.55.0
