> From: fengchengwen [mailto:fengcheng...@huawei.com] > Sent: Sunday, 24 April 2022 05.45 > > The root cause is: when the xstats is NULL and n less than required > number of > elements is zero, the return value of rte_eth_xstats_get is ambiguous > from > rte_ethdev.h's declaration. > > But the implementation of rte_eth_xstats_get return required number of > elements > when xstats is NULL and n less than required number of elements. > > There are two modification schemes: > a) the value of xstats cannot be NULL, and the value of n must be > greater than > or equal to the required number, otherwise, an error code is > returned. > b) define the behavior as the same as rte_eth_xstats_get_names, which > means return > required number of elelement when xstats is NULL and n less than > required number > of elements. > > I prefer the scheme a because rte_eth_xstats_get and > rte_eth_xstats_get_name are > symbiotic, and it's not necessary to both implement the same logic. > > Also for scheme a, there is no need to modify the PMD implementation. > > What about your opinions ?
This is an excellent proposal. And if the documentation for rte_eth_xstats_get() refers to rte_eth_xstats_get_names() for getting the number of elements, it is perfect. > > On 2022/4/21 14:49, Andrew Rybchenko wrote: > > On 4/16/22 04:38, Stephen Hemminger wrote: > >> On Sat, 16 Apr 2022 09:07:45 +0800 > >> Chengwen Feng <fengcheng...@huawei.com> wrote: > >> > >>> Currently the telemetry xstats uses rte_eth_xstats_get() to > retrieve > >>> the number of elements. But the value to be returned when the > parameter > >>> 'xstats' is NULL is not specified, some PMDs (eg. > hns3/ipn3ke/mvpp2/ > >>> axgbe) return zero while others return the required number of > elements. > >> > >> Lets fix the PMD's this impacts other code as well. > > > > +1 > > > > . >
