Re: [PATCH 5/6] kconfig: implement KCONFIG_PROBABILITY for randconfig

[Michal Marek <mmarek@suse.cz>]

On 22.4.2013 23:31, Yann E. MORIN wrote:
> diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
> index 13ddf11..8d8d853 100644
> --- a/scripts/kconfig/confdata.c
> +++ b/scripts/kconfig/confdata.c
> @@ -1106,7 +1106,16 @@ static void set_all_choice_values(struct symbol *csym)
>  void conf_set_all_new_symbols(enum conf_def_mode mode)
>  {
>  	struct symbol *sym, *csym;
> -	int i, cnt;
> +	int i, cnt, prob = 50;
> +
[...]
>  			case def_random:
> -				cnt = sym_get_type(sym) == S_TRISTATE ? 3 : 2;
> -				sym->def[S_DEF_USER].tri = (tristate)(rand() % cnt);
> +				cnt = (rand() % 100) - (100 - prob);
> +				if (cnt < 0)
> +					sym->def[S_DEF_USER].tri = no;
> +				else
> +					if ((sym_get_type(sym) == S_TRISTATE)
> +					    && (cnt > prob/2))
> +						sym->def[S_DEF_USER].tri = mod;
> +					else
> +						sym->def[S_DEF_USER].tri = yes;

Previously, the distribution was 50%-50% for boolean options and
33%-33%-33% for tristate options. Now the default for tristate options
changed to 50%-25%-25% (no-mod-yes). Wouldn't it make more sense to have
a special case for KCONFIG_PROBABILITY not set, that would use the same
distribution as before. I.e.

if (prob == -1) {
	cnt = sym_get_type(sym) == S_TRISTATE ? 3 : 2;
	sym->def[S_DEF_USER].tri = (tristate)(rand() % cnt);
} else {
	/* new math */
}

Not building half of all drivers is rather boring :)

Thanks,
Michal