On 2024/9/9 8:13, Stephen Hemminger wrote: > On Sun, 8 Sep 2024 23:31:36 +0100 > Dpdk Newbie <dpdkuse...@gmail.com> wrote: > >> Hi. I am using Intel (i210) and AWS ENA network interface cards. >> >> I would like to measure the following RX latencies: >> >> 1) NIC to DPDK packet ring buffer >> 2) DPDK packet ring buffer to application via rte_eth_rx_burst.
Some packet generator support delay measurement, could construct two tests: 1. run with enabled hairpin some NIC support hairpin (the data write to memory and resend by hardware again) if the NIC don't support hairpin, could use mac outer loop. 2. run with normal mode According compare the two delay. >> >> I don't mind measuring in nanoseconds or CPU cycles. >> >> Unfortunately I cannot find any mention of hardware timestamps. >> >> I found brief references to mbuf containing a timestamp in the dynamic >> fields, but nothing definitive. >> >> Could someone please clarify what the situation is? >> >> Thanks, > > Depends on the hardware, and the dynamic field for rx timestamp As I know, this Rx timestamp dynamic field is mainly used by PTP(IEEE1588). > also varies in its clock value. Some are ticks, some are us, some are ns; > and the base is arbitrary so difficult to use for packet capture. Yes > . >
