Re: [RFC] random: use per lcore state

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 11 Sep 2023 11:00:46 +0200
Mattias Rönnblom <hofors@lysator.liu.se> wrote:

> > uint64_t rte_rand_r(struct rte_rand_state * const state);
> > void rte_srand_r(struct rte_rand_state * const state, uint64_t
> > seed); uint64_t rte_rand_max_r(struct rte_rand_state * const state,
> > uint64_t upper_bound); double rte_drand_r(struct rte_rand_state *
> > const state, void);
> > 
> > For this to work, we would have to make struct rte_rand_state
> > public, and the application would need to allocate it. (At least
> > one instance per thread that uses it, obviously.) 
> 
> Yes, and that will come at a pretty severe API complexity cost.
> 
> Besides the obvious complexities, it may also lead the user to
> believe the rte_rand() is not MT safe for any thread, since that's
> how it works in glibc (rand() versus rand_r()).

Actual rand state implementation could be hidden by having an
allocation/create/new function.