Signed-off-by: Remy Horton <remy.horton at intel.com> --- doc/guides/prog_guide/poll_mode_drv.rst | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/doc/guides/prog_guide/poll_mode_drv.rst b/doc/guides/prog_guide/poll_mode_drv.rst index 7698692..802fb8f 100644 --- a/doc/guides/prog_guide/poll_mode_drv.rst +++ b/doc/guides/prog_guide/poll_mode_drv.rst @@ -299,10 +299,27 @@ 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. +of statistics. Accessing these from application programs is done via two +functions: + +* ``rte_eth_xstats_get``: Fills in an array of ``struct rte_eth_xstat`` + with extended statistics. +* ``rte_eth_xstats_get_names``: Fills in an array of + ``struct rte_eth_xstat_name`` with extended statistic name lookup + information. + +Each ``struct rte_eth_xstat`` contains an identifier and value pair, and +each ``struct rte_eth_xstat_name`` contains an identifier and string pair. +Each identifier within ``struct rte_eth_xstat`` must have a corresponding +entry in ``struct rte_eth_xstat_name`` with a matching identifier. These +identifiers, as well as the number of extended statistic exposed, must +remain constant during runtime. + +Note that extended statistic identifiers are driver-specific, and hence +might not be the same for different ports. Although it is expected that +drivers will make the identifiers used within ``struct rte_eth_xstat`` and +``struct rte_eth_xstat_name`` entries match the entries' array index, this +property should not be relied on by applications for lookups. 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 -- 2.5.5
