On Thu, 5 Dec 2024 00:50:24 +0300 Dmitry Kozlyuk <dmitry.kozl...@gmail.com> wrote:
> Hi Igor, > > 2024-10-23 02:25 (UTC+0300), Igor Gutorov: > > I've noticed an issue of `rte_memory_get_nchannel()` or > > `rte_memory_get_nrank()` always returning zero regardless of the -n or > > -r options set. > > > > I think this is due to `--in-memory` forcing `conf->no_shconf = 1` > > [1], which leads to `rte_eal_memdevice_init()` never being executed > > [2]. > > > > I do not fully understand the context of the code, but I can submit a > > patch that simply removes the `internal_conf->no_shconf == 0` check in > > `rte_eal_memory_init()` and so always calls > > `rte_eal_memdevice_init()`. Would that be ok or is there a better way? > > Alternatively, does `(internal_conf->no_shconf == 0 || > > internal_conf->in_memory == 1) && ...` make sense here? > > Well spotted! Yes, the check seems unneeded. > > > And one more thing, the 9.1.4 section of the getting started guide > > states that the number of memory ranks is auto-detected by default, > > but I can't find any code that performs the auto-detection - am I > > missing something, or is the documentation wrong here? > > The doc is clearly wrong. > Git says this piece originates from TestPMD documentation, > so maybe "auto-detected" refers to some defaults for mempools: Doc should be reworded to some thing like "if not defined, reasonable default values are used instead". It is difficult to do auto-detection of memory layout optimum spread. The Linux kernel provides no visible API for finding out; and the only way I know is digging into DMI data (see dmidecode). But DMI data is only readable as root, can be wrong, and doesn't really match in a cloud environment.
