Re: [dpdk-dev] [PATCH v3 02/11] doc: add extended statistics to prog_guide

["Tahhan, Maryam" <maryam.tahhan@intel.com>]

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Harry van Haaren
> Sent: Thursday, October 22, 2015 4:48 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v3 02/11] doc: add extended statistics to
> prog_guide
> 
> Add extended statistic section to the programmers guide, poll mode driver
> section. This section describes how the strings stats are formatted, and how
> the client code can use this to gather information about the stat.
> 
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> ---
>  doc/guides/prog_guide/poll_mode_drv.rst | 51
> ++++++++++++++++++++++++++++++++-
>  1 file changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/guides/prog_guide/poll_mode_drv.rst
> b/doc/guides/prog_guide/poll_mode_drv.rst
> index 8780ba3..44cc9ce 100644
> --- a/doc/guides/prog_guide/poll_mode_drv.rst
> +++ b/doc/guides/prog_guide/poll_mode_drv.rst
> @@ -1,5 +1,5 @@
>  ..  BSD LICENSE
> -    Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
> +    Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
>      All rights reserved.
> 
>      Redistribution and use in source and binary forms, with or without @@ -
> 294,3 +294,52 @@ Ethernet Device API  ~~~~~~~~~~~~~~~~~~~
> 
>  The Ethernet device API exported by the Ethernet PMDs is described in the
> *DPDK API Reference*.
> +
> +Extended Statistics API
> +~~~~~~~~~~~~~~~~~~~~~~~
> +
> +The extended statistics API allows each individual PMD to expose a
> +unique set of statistics. The client of the API provides an array of
> +``struct rte_eth_xstats`` type. Each ``struct rte_eth_xstats`` contains
> +a string and value pair. The amount of xstats exposed, and position of
> +the statistic in the array must remain constant during runtime.
> +
> +A naming scheme exists for the strings exposed to clients of the API.
> +This is to allow scraping of the API for statistics of interest. The
> +naming scheme uses strings split by a single underscore ``_``. The scheme is
> as follows:
> +
> +* direction
> +* detail 1
> +* detail 2
> +* detail n
> +* unit
> +
> +Examples of common statistics xstats strings, formatted to comply to
> +the scheme proposed above:
> +
> +* ``rx_bytes``
> +* ``rx_crc_errors``
> +* ``tx_multicast_packets``
> +
> +The scheme, although quite simple, allows flexibility in presenting and
> +reading information from the statistic strings. The following example
> +illustrates the naming scheme:``rx_packets``. In this example, the
> +string is split into two components. The first component ``rx``
> +indicates that the statistic is associated with the receive side of the
> +NIC.  The second component ``packets`` indicates that the unit of measure is
> packets.
> +
> +A more complicated example: ``tx_size_128_to_255_packets``. In this
> +example, ``tx`` indicates transmission, ``size``  is the first detail,
> +``128`` etc are more details, and ``packets`` indicates that this is a packet
> counter.
> +
> +Some additions in the metadata scheme are as follows:
> +
> +* If the first part does not match ``rx`` or ``tx``, the statistic does
> +not
> +  have an affinity with either recieve of transmit.
> +
> +* If the first letter of the second part is ``q`` and this ``q`` is
> +followed
> +  by a number, this statistic is part of a specific queue.
> +
> +An example where queue numbers are used is as follows: ``tx_q7_bytes``
> +which indicates this statistic applies to queue number 7, and
> +represents the number of transmitted bytes on that queue.
> --
> 1.9.1
Acked-by: Maryam Tahhan <maryam.tahhan@intel.com>