From lib/librte_mbuf/rte_mbuf_core.h:
|605 /** Valid if PKT_RX_TIMESTAMP is set. The unit and time reference
606 * are not normalized but are always the same for a given port. 607 *
Some devices allow to query rte_eth_read_clock that will return the 608
* current device timestamp. 609 */ 610 uint64_t timestamp;|
|I believe the timestamp in mbuf is set by the NIC. If it isn't,
librte_eventdev sets it using rte_get_tsc_cycle(). From
/lib/librte_eventdev/rte_event_eth_rx_adapter.h |
22 * The adapter uses a EAL service core function for SW based packet transfer
23 * and uses the eventdev PMD functions to configure HW based packet transfer
24 * between the ethernet device and the event device. For SW based packet
25 * transfer, if the mbuf does not have a timestamp set, the adapter adds a
26 * timestamp to the mbuf using rte_get_tsc_cycles(), this provides a more
27 * accurate timestamp as compared to if the application were to set the time
28 * stamp since it avoids event device schedule latency.
Hope that helps!
On 11/18/2019 7:59 PM, Gokul Bargaje wrote:
Hi,
The timestamp assigned to packet at the time of enqueue (value of timestamp
field in mbuf), is it in milliseconds or microseconds or in cpu cycles?
How this timestamp is calculated? Is it calculated using the *rte_cycles.h*?
Thanks in advance!
--Gokul
--
Archit Pandey
Senior Year Undergraduate Student
Department of Computer Science and Engineering
National Institute of Technology Karnataka
Surathkal, India
