Re: [OE-core][PATCH RFC v2 12/19] meta/lib/oe/tune.py: add riscv_pkgarch()

[Mark Hatle <mark.hatle@kernel.crashing.org>]

On 9/30/26 11:38 AM, Trevor Gamblin wrote:
> Create a new function to help match RISC-V ISA extension combinations
> against recognized profile strings (e.g. 'rva22u64'), so that we can use
> simpler patterns for naming things like sstate/build paths.
> 
> Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
> ---
>   meta/lib/oe/tune.py | 29 +++++++++++++++++++++++++++++
>   1 file changed, 29 insertions(+)
> 
> diff --git a/meta/lib/oe/tune.py b/meta/lib/oe/tune.py
> index 7296f39e66..0d8e4417e7 100644
> --- a/meta/lib/oe/tune.py
> +++ b/meta/lib/oe/tune.py
> @@ -90,3 +90,32 @@ def riscv_isa_to_tune(isa):
>       # Eliminate duplicates, but preserve the order
>       feature = list(dict.fromkeys(feature))
>       return ' '.join(feature)
> +
> +# riscv_pkgarch(features, exact_pkgarch)
> +#
> +# Prefer a RISCV_PROFILES name (plus any extensions enabled on top of it) as the
> +# package arch fragment, since otherwise the full ISA extension list will exceed
> +# what the sstate class can handle. When several profiles match, the one with
> +# the most extensions is preferred, as it is the more specific/clearer match.
> +# If there's no clear profile matching the extension list, then fall back to
> +# exact_pkgarch.
> +def riscv_pkgarch(features, exact_pkgarch):
> +    if not features:
> +        return exact_pkgarch
> +
> +    current = set(features.split())
> +
> +    best_match = None
> +    best_features = None
> +    for name in RISCV_PROFILES:

Where is 'RISCV_PROFILES' defined?

As long as someone is willing to keep this up to date with all of the new 
profiles, I don't have a concern with it.

On my AMD platforms, we have dynamic (user defined) ISA for our parts, the users 
don't really use 'profiles', but select individual isa components.  I would LIKE 
(but only because it's easier for me) a way to see the ISA and not have it 
converted back to a profile.  However, if profiles are the risc-v ISA standard, 
I'm fine without a way to disable the translation.

--Mark

> +        profile_features = set(riscv_isa_to_tune(name).split())
> +        if profile_features.issubset(current):
> +            if best_features is None or len(profile_features) > len(best_features):
> +                best_match = name
> +                best_features = profile_features
> +
> +    if best_match is None:
> +        return exact_pkgarch
> +
> +    extra = sorted(current - best_features)
> +    return '_'.join([best_match] + extra)
>