Struct PlanPreference 

pub struct PlanPreference {
    pub max_workspace_bytes: usize,
    pub allow_sm90a: bool,
    pub prefer_backend: Option<BackendKind>,
}

Hints that influence kernel selection inside a plan’s select method.

The fields are intentionally generic across kernel families — each op category may layer its own *PlanPreference wrapper on top (e.g. GroupedPlanPreference adds grouped-specific knobs) that embeds this struct.

Fields

max_workspace_bytes: usize

Maximum workspace the caller is willing to provide. The selector only considers kernels whose workspace size for the descriptor fits in this budget. Use usize::MAX to disable the constraint.

allow_sm90a: bool

Allow Hopper-specialized (sm_90a) kernels in selection. Has no effect when the sm90a feature is off in the underlying kernel crate (no such kernels exist in the build).

prefer_backend: Option<BackendKind>

Force a particular backend at plan-selection time, bypassing the plan’s built-in heuristic.

None (the default) lets the plan’s per-op-category heuristic decide. Some(BackendKind::Cublas) / Some(BackendKind::Cutlass) override the heuristic when a caller has profiling-driven information the heuristic doesn’t have (or wants deterministic kernel selection for golden-output testing).

Plans surface their actual choice through their sku() accessor — inspect sku.backend to see what the heuristic picked.

Returns Error::Unsupported from select if the requested backend doesn’t have a kernel for the requested (layout, epilogue, element) triple. For example, the cuBLAS backend doesn’t support EpilogueKind::BiasRelu (cuBLAS has no fused-bias-activation GEMM); forcing it on a Bias* epilogue returns an error rather than silently falling back to CUTLASS.

Trait Implementations

impl Clone for PlanPreference

fn clone(&self) -> PlanPreference

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for PlanPreference

impl Debug for PlanPreference

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for PlanPreference

fn default() -> PlanPreference

Returns the “default value” for a type.