Struct BatchSizer 

pub struct BatchSizer {
    pub vram_utilization: f32,
}

Computes the maximum batch size that fits safely within VRAM.

Uses the exact per-pair device memory layout of the GPU compare kernel, no field-length estimation required because every string is padded to STRING_STRIDE bytes on the device regardless of actual content.

Per-pair device memory layout

Buffer	Bytes per pair
d_data_a + d_data_b (u8, STRING_STRIDE each)	2 times n_fields times 64
d_lens_a + d_lens_b (u16)	2 times n_fields times 2
d_ids_a + d_ids_b (u64)	2 times 8
d_weights + d_probs (f32)	2 times 4
d_levels (u32)	n_fields times 4

Total: n_fields times 136 + 24 bytes per pair (exact, no estimation).

Example

use zer_compute::batch_sizer::BatchSizer;

let sizer = BatchSizer::new();
// 3 GB available VRAM (e.g. after OS + model overhead), 10 fields
let available = 3u64 * 1024 * 1024 * 1024;
let max = sizer.max_batch_size(available, 10);
assert!(max > 1_000_000, "should easily fit millions of pairs");

Fields

vram_utilization: f32

Fraction of available VRAM to commit to the comparison batch. Default: 0.75.

Implementations

impl BatchSizer

pub fn new() -> Self

pub fn with_utilization(self, fraction: f32) -> Self

Override the utilization fraction (0.0 < fraction ≤ 1.0).

pub fn max_batch_size( &self, available_vram_bytes: u64, num_fields: usize, ) -> usize

Compute the maximum number of pairs that fit in available_vram_bytes VRAM for a schema with num_fields fields.

The formula matches the GPU compare kernel buffer layout exactly, no avg_field_len estimate is needed because device buffers always use STRING_STRIDE bytes per string.

Returns at least 1 so callers never divide by zero.

pub const fn min_batch_for_gpu() -> usize

Minimum batch size to justify a GPU kernel launch. Batches smaller than this are routed to the CPU path transparently.

Trait Implementations

impl Clone for BatchSizer

fn clone(&self) -> BatchSizer

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BatchSizer

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

Formats the value using the given formatter.

impl Default for BatchSizer

fn default() -> Self

Returns the “default value” for a type.