Hello Bruce, On Tue, Apr 1, 2025 at 4:08 PM Bruce Richardson <bruce.richard...@intel.com> wrote: > > On Mon, Mar 24, 2025 at 05:30:26PM +0000, Bruce Richardson wrote: > > Traditionally, DPDK has had a direct mapping of internal lcore-ids, to > > the actual core numbers in use. With higher core count servers becoming > > more prevalent the issue becomes one of increasing memory footprint when > > using such a scheme, due to the need to have all arrays dimensioned for > > all cores on the system, whether or not those cores are in use by the > > app. > > > > Therefore, the decision was made in the past to not expand the > > build-time RTE_MAX_LCORE value beyond 128. Instead, it was recommended > > that users use the "--lcores" EAL parameter to take the high-numbered > > cores they wish to use and map them to lcore-ids within the 0 - 128 > > range. While this works, this is a little clunky as it means that > > instead of just passing, for example, "-l 130-139", the user must > > instead pass "--lcores 0@130,1@131,2@132,3@133,...." > > > > This patchset attempts to simplify the situation by adding a new flag to > > do this mapping automatically. To use cores 130-139 and map them to ids > > 0-9 internally, the EAL args now become: "-l 130-139 --map-lcore-ids", > > or using the shorter "-M" version of the flag: "-Ml 130-139". > > > > Adding this new parameter required some rework of the existing arg > > parsing code, because in current DPDK the args are parsed and checked in > > the order they appear on the commandline. This means that using the > > example above, the core parameter 130-139 will be rejected immediately > > before the "map-lcore-ids" parameter is seen. To work around this, the > > core (and service core) parameters are not parsed when seen, instead > > they are only saved off and parsed after all arguments are parsed. The > > "-l" and "-c" parameters are converted into "--lcores" arguments, so all > > assigning of lcore ids is done there in all cases. > > > > RFC->v2: > > * converted printf to DEBUG log > > * added "-M" as shorter version of flag > > * added documentation > > * renamed internal API that was changed to avoid any potential hidden > > runtime issues. > > > > Bruce Richardson (3): > > eal: centralize core parameter parsing > > eal: convert core masks and lists to core sets > > eal: allow automatic mapping of high lcore ids > > > Ping for review. > > At a high level, does this feature seem useful to users?
This seems useful, though I am not I would touch the existing options. I would have gone with a simple -L option (taking the same kind of input than -l but with new behavior), and not combine a flag with existing options. I scanned through the series, not much to say. Maybe add a unit test for new cmdline option. -- David Marchand
