Re: [PATCH v3 0/9] rework EAL argument parsing

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

On Fri, Jul 18, 2025 at 03:33:46PM +0100, Bruce Richardson wrote:
> 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 two 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. 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.
> 

Apologies, forgot the diff from the RFC v2:

* Added 3 new initial patches, one for minor build-system addition, and two
  for functionality in argparse to allow the user-callback help function to
  be maintained as we move to argparse.
* Added doc updates in the first EAL patch adding the long options
* Fixed ASAN issues by adding a patch to properly clean up EAL init - both
  memory allocations and fixing the run-once flag
* Put ifdefs around the linux-only or unix-only options in EAL patch 2
* Updated args to handle numa-mem and numa-limit as equivalent socket-mem
  and socket-limit

> 
> Bruce Richardson (9):
>   build: add define for the OS environment name
>   argparse: export function to print help text for object
>   argparse: allow user-override of help printing
>   eal: add long options for each short option
>   eal: define the EAL parameters in argparse format
>   eal: gather EAL args before processing
>   eal: ensure proper cleanup on EAL init failure
>   eal: combine parameter validation checks
>   eal: simplify handling of conflicting cmdline options
> 
>  config/meson.build                        |    1 +
>  doc/guides/contributing/design.rst        |    2 +-
>  doc/guides/linux_gsg/eal_args.include.rst |   20 +-
>  doc/guides/prog_guide/argparse_lib.rst    |   16 +
>  lib/argparse/rte_argparse.c               |   46 +-
>  lib/argparse/rte_argparse.h               |   21 +-
>  lib/eal/common/eal_common_memory.c        |    3 +-
>  lib/eal/common/eal_common_options.c       | 1299 +++++++++++----------
>  lib/eal/common/eal_options.h              |  102 +-
>  lib/eal/common/eal_private.h              |   11 +
>  lib/eal/freebsd/eal.c                     |  245 +---
>  lib/eal/linux/eal.c                       |  470 +-------
>  lib/eal/linux/eal_memory.c                |    2 +-
>  lib/eal/meson.build                       |    2 +-
>  lib/eal/windows/eal.c                     |  156 +--
>  lib/meson.build                           |    1 +
>  16 files changed, 954 insertions(+), 1443 deletions(-)
> 
> --
> 2.48.1
>