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| author | Reshma Pattan <reshma.pattan@intel.com> | 2018-10-04 13:23:59 +0100 |
|---|---|---|
| committer | Thomas Monjalon <thomas@monjalon.net> | 2018-11-19 01:35:17 +0100 |
| commit | 999aa0635c5ccd56b0ef728309d393c25aa4f5c9 (patch) | |
| tree | 62fa3447f68a8c3b1b49fd43dc4c4a37aa4d440f | |
| parent | eaee9659037e7ee7c77feba76c1d940929f4a8af (diff) | |
doc: update timestamp validity for latency measurement
Updated the doc on how packets are marked to identify
their timestamp as valid and considered for latency
measurement.
Suggested-by: Bao-Long Tran <longtb5@viettel.com.vn>
Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
| -rw-r--r-- | doc/guides/prog_guide/metrics_lib.rst | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/doc/guides/prog_guide/metrics_lib.rst b/doc/guides/prog_guide/metrics_lib.rst index 5cbe17c903..e68e4e7431 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. |