Updated the doc on how packets are marked to identify their timestamp as valid and considered for latency measurement.
Suggested-by: Bao-Long Tran <long...@viettel.com.vn> Signed-off-by: Reshma Pattan <reshma.pat...@intel.com> --- This change is relevant to the below patch and must be applied after that. http://patches.dpdk.org/patch/45328/ --- doc/guides/prog_guide/metrics_lib.rst | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/doc/guides/prog_guide/metrics_lib.rst b/doc/guides/prog_guide/metrics_lib.rst index 5cbe17c90..e68e4e743 100644 --- a/doc/guides/prog_guide/metrics_lib.rst +++ b/doc/guides/prog_guide/metrics_lib.rst @@ -271,3 +271,12 @@ de-initialise the latency library. .. code-block:: c rte_latencystats_uninit(); + +Timestamp and latency calculation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The Latency stats library marks the time in the timestamp field of the +mbuf for the ingress packets and sets the ``PKT_RX_TIMESTAMP`` flag of +``ol_flags`` for the mbuf to indicate the marked time as a valid one. +At the egress, the mbufs with the flag set are considered having valid +timestamp and are used for the latency calculation. -- 2.17.1
