diff mbox series

doc: update timestamp validity for latency measurement

Message ID 1538655839-32339-1-git-send-email-reshma.pattan@intel.com (mailing list archive)
State Accepted, archived
Delegated to: Thomas Monjalon
Headers show
Series doc: update timestamp validity for latency measurement | expand

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Pattan, Reshma Oct. 4, 2018, 12:23 p.m. UTC
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>
---
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(+)

Comments

Kovacevic, Marko Nov. 14, 2018, 10:14 a.m. UTC | #1
> 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>
>
> +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.

Acked-by: Marko Kovacevic <marko.kovacevic@intel.com>
Thomas Monjalon Nov. 19, 2018, 12:37 a.m. UTC | #2
04/10/2018 14:23, Reshma Pattan:
> 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>
> ---
> This change is relevant to the below patch and must be applied
> after that.
> http://patches.dpdk.org/patch/45328/

It's better to squash doc & code patches together, when possible.

Applied, thanks
diff mbox series

Patch

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.