Re: [PATCH v7 00/13] Simplify running with high-numbered CPUs

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Jul 23, 2025 at 05:19:58PM +0100, Bruce Richardson wrote:
> The ultimate of this patchset is to make it easier to run on systems
> with large numbers of cores, by simplifying the process of using core
> numbers >RTE_MAX_LCORE. The new EAL args "--lcores-remapped", also
> shortened to just "-L", and "--lcoreid-base", are added to DPDK to
> support this. However, in order to enable the addition of these new
> flags, the first 10 patches of this set do cleanups, for reasons
> explained below.
> 
> When processing cmdline arguments in DPDK, we always do so with very
> little context. So, for example, when processing the "-l" flag, we have
> no idea whether there will be later a --proc-type=secondary flag. We
> have all sorts of post-arg-processing checks in place to try and catch
> these scenarios.
> 
> To improve this situation, this patchset tries to simplify the handling
> of argument processing, by explicitly doing an initial pass to collate
> all arguments into a structure. Thereafter, the actual arg parsing is
> done in a fixed order, meaning that e.g. when processing the
> --main-lcore flag, we have already processed the service core flags. We
> also can far quicker and easier check for conflicting options, since
> they can all be checked for NULL/non-NULL in the arg structure
> immediately after the struct has been populated.
> 
> To do the initial argument gathering, this RFC uses the existing
> argparse library in DPDK. With recent changes, and a few additional
> patches at the start of this set, this library now meets our needs for
> EAL argument parsing and allows us to not need to do direct getopt
> argument processing inside EAL at all.
> 
> An additional benefit of this work is that the argument parsing for EAL
> is much more centralised into common options and the options list file.
> This single list with ifdefs makes it clear to the viewer what options
> are common across OS's, vs what are unix-only or linux-only.
> 
> Once the cleanup and rework is done, adding the new options for
> remapping cores becomes a lot simpler, since we can very easily check
> for scenarios like multi-process and handle those appropriately.
> 
> V7:
> * expand the scope of the patchset beyond just cleanup to add in the
>   extra 3 patches for -L and --lcoreid-base option.
> 
Recheck-request: rebase=main, iol-abi-testing