> From: Jastrzebski, MichalX K > Sent: Tuesday, April 11, 2017 5:37 PM > To: dev@dpdk.org > Cc: Jain, Deepak K <deepak.k.j...@intel.com>; Van Haaren, Harry > <harry.van.haa...@intel.com>; > Piasecki, JacekX <jacekx.piase...@intel.com>; Kozak, KubaX > <kubax.ko...@intel.com>; Kulasek, > TomaszX <tomaszx.kula...@intel.com> > Subject: [PATCH v5 1/3] ethdev: new xstats API add retrieving by ID > > From: Jacek Piasecki <jacekx.piase...@intel.com> > > Extended xstats API in ethdev library to allow grouping of stats > logically so they can be retrieved per logical grouping managed > by the application. > Changed existing functions rte_eth_xstats_get_names and > rte_eth_xstats_get to use a new list of arguments: array of ids > and array of values. ABI versioning mechanism was used to > support backward compatibility. > Introduced two new functions rte_eth_xstats_get_all and > rte_eth_xstats_get_names_all which keeps functionality of the > previous ones (respectively rte_eth_xstats_get and > rte_eth_xstats_get_names) but use new API inside. > Both functions marked as deprecated. > Introduced new function: rte_eth_xstats_get_id_by_name > to retrieve xstats ids by its names. > > test-pmd: add support for new xstats API retrieving by id in > testpmd application: xstats_get() and > xstats_get_names() call with modified parameters. > > proc_info: add support for new xstats API retrieving by id to > proc_info application. There is a new argument --xstats-ids > in proc_info command line to retrieve statistics given by ids. > E.g. --xstats-ids="1,3,5,7,8" > > doc: add description for modified xstats API > Documentation change for modified extended statistics API functions. > The old API only allows retrieval of *all* of the NIC statistics > at once. Given this requires a MMIO read PCI transaction per statistic > it is an inefficient way of retrieving just a few key statistics. > Often a monitoring agent only has an interest in a few key statistics, > and the old API forces wasting CPU time and PCIe bandwidth in retrieving > *all* statistics; even those that the application didn't explicitly > show an interest in. > The new, more flexible API allow retrieval of statistics per ID. > If a PMD wishes, it can be implemented to read just the required > NIC registers. As a result, the monitoring application no longer wastes > PCIe bandwidth and CPU time. > > Signed-off-by: Jacek Piasecki <jacekx.piase...@intel.com> > Signed-off-by: Kuba Kozak <kubax.ko...@intel.com> > Signed-off-by: Tomasz Kulasek <tomaszx.kula...@intel.com>
As part of this patchset 3 functions were added to struct eth_dev_ops, to provide more flexible xstats() APIs. This patchset uses symbol versioning to keep ABI stable. I have checked ABI using ./devtools/validate-abi.sh script for both GCC 5.4.0 and Clang 3.8.0. GCC indicates Compatible, while Clang says there is a single Medium issue, which I believe to be a false positive (details below). The clang Medium issue is described as follows by the ABI report; - struct rte_eth_dev : Change: Size of field dev_ops has been changed from 624 bytes to 648 bytes [HvH: due to adding 3 xstats function pointers to end of struct] Effect: Previous accesses of applications and library functions to this field and fields at higher positions of the structure definition may be broken. The reason I believe this is a false positive is that the "dev_ops" field is defined in the rte_eth_dev struct as follows: const struct eth_dev_ops *dev_ops; Any accesses made to dev_ops will be by this pointer-dereference, so the *size* of dev_ops *in* rte_eth_dev struct is still a pointer - it hasn't changed. Hence "accesses to this field and fields at higher positions of the structure" will not be changed - the pointer in the rte_eth_dev struct remains a pointer. Acked-by: Harry van Haaren <harry.van.haa...@intel.com>
