On Tue, 30 Jul 2024 at 13:45, Bruce Richardson <bruce.richard...@intel.com> wrote:
> On Tue, Jul 30, 2024 at 11:06:56AM +0530, Prashant Upadhyaya wrote: > > On Mon, 29 Jul 2024 at 23:13, Dmitry Kozlyuk > > <[1]dmitry.kozl...@gmail.com> wrote: > > > > 2024-07-29 22:18 (UTC+0530), Prashant Upadhyaya: > > > Hi, > > > > > > I have 4 ethernet interfaces available as PCI devices. > > > The PCI addresses are known. > > > When I start my DPDK application, it starts up properly and > > assigns the > > > port numbers to them as 0, 1, 2, 3 expectedly. > > > > > > However, is there a way I can force that a particular PCI address > > should be > > > identified as port 0 by DPDK, another one as port 1 and so forth ? > > > Does passing the arguments like -a <address1> -a <address2> to > > rte_eal_init > > > ensure that, or is there any other way, or is there no way ? > > > > > > I am on 24.03 > > > > > > Regards > > > -Prashant > > Hi, > > Why do you need specific port numbers assigned to devices? > > If you're going to use devices for different purposes, > > you'd better have an application-level configuration > > to specify PCI addresses to use for each purpose. > > Iterate devices to match the address and find the port number. > > It is also possible to disable automatic probing with "-a 0:0.0", > > then to use rte_dev_probe() + rte_dev_event_callback_register() > > to add devices and to get their port numbers. > > However, this API, strictly speaking, does not guarantee > > that the numbers will be assigned sequentially. > > One advantage of using hot-plug is that you can build devargs > > from within the application (or from configuration). > > Refer to "rte_dev.h" in any case. > > Multiple "-a" don't work the way you've described. > > > > Thanks Dmitry. Ok, so if I have the port number with me, and I know it > > corresponds to a PCI device, how do I find out the PCI address of this > > device corresponding to this port number. I believe I can > > do rte_eth_dev_info_get to get the struct rte_eth_dev_info and from > > there the rte_device, but what after that ? I saw some references > > to RTE_DEV_TO_PCI but that macro isn't available for compilation after > > DPDK is installed as it is an internal header file and thus not a > macro > > for application usage and wouldn't compile at application level. > > Regards > > -Prashant > > > The PCI device id is used as the device name in that case so rte_dev_name > should get you what you want. > > I'd also +1 the suggestion of having your app hotplug in the devices > post-init, if you want specific devices to have specific ids. Although it > is not guaranteed, DPDK does currently assign the ids sequentially. I've > used this approach myself in the past in some test apps where I wanted > ports in a particular sequence. > > /Bruce > Thanks Bruce, makes sense. Regards -Prashant
