+- To provide the packet send scheduling on mbuf timestamps the ``tx_pp``
+ parameter should be specified, RTE_MBUF_DYNFIELD_TIMESTAMP_NAME and
+ RTE_MBUF_DYNFLAG_TIMESTAMP_NAME should be registered by application.
+ When PMD sees the RTE_MBUF_DYNFLAG_TIMESTAMP_NAME set on the packet
+ being sent it tries to synchronize the time of packet appearing on
+ the wire with the specified packet timestamp. It the specified one
+ is in the past it should be ignored, if one is in the distant future
+ it should be capped with some reasonable value (in range of seconds).
+ These specific cases ("too late" and "distant future") can be optionally
+ reported via device xstats to assist applications to detect the
+ time-related problems.
+
+ The timestamp upper "too-distant-future" limit
+ at the moment of invoking the Tx burst routine
+ can be estimated as ``tx_pp`` option (in nanoseconds) multiplied by 2^23.
+ Please note, for the testpmd txonly mode,
+ the limit is deduced from the expression::
+
+ (n_tx_descriptors / burst_size + 1) * inter_burst_gap
+
+ There is no any packet reordering according timestamps is supposed,
+ neither within packet burst, nor between packets, it is an entirely
+ application responsibility to generate packets and its timestamps
+ in desired order. The timestamps can be put only in the first packet
+ in the burst providing the entire burst scheduling.
+