This RFC is just an initial prototype of one approach we may want to take to help improve management of EAL cmdline arguments. Although not complete (no account taken yet for BSD or Windows), it's hopefully complete enough to give an idea of what I think would improve the handling.
BACKGROUND: - The first problem that led to this work was that of providing a way for users to easily provide a set of CPU cores to DPDK where the CPU ids are >= RTE_MAX_LCORE - There are a number of solutions which were discussed for this, most of which involved automatically remapping CPU ids to lcore ids starting at zero. - However, in discussion with David M. at the last DPDK Summit in Prague, he pointed out the main difficulty with all these approaches in that they don't work with multi-process, since we can't reuse lcore id numbers in secondary process. - This in turn lead to a realisation that 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. This patchset therefore 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 some minor tweaking, this meets our needs for EAL argument parsing and allows us to not need to do direct getopt argument processing inside EAL at all. Bruce Richardson (7): eal: add long options for each short option argparse: add support for string and boolean args argparse: make argparse EAL-args compatible eal: define the EAL parameters in argparse format eal: gather EAL args before processing eal: combine parameter validation checks eal: simplify handling of conflicting cmdline options app/test/test_argparse.c | 46 +- lib/argparse/rte_argparse.c | 46 +- lib/argparse/rte_argparse.h | 9 +- lib/eal/common/eal_common_memory.c | 3 +- lib/eal/common/eal_common_options.c | 1435 ++++++++++++++++----------- lib/eal/common/eal_options.h | 99 +- lib/eal/common/eal_private.h | 11 + lib/eal/linux/eal.c | 378 +------ lib/eal/meson.build | 2 +- 9 files changed, 966 insertions(+), 1063 deletions(-) -- 2.48.1
