Struct CompressedDeviceBuffer 

pub struct CompressedDeviceBuffer { /* private fields */ }

Host-side descriptor for a compressed device allocation.

Tracks the logical size, the physically reserved (granularity-aligned) size, and an observed compression ratio that the application can update as it learns how compressible its data is. The descriptor never owns a GPU pointer here — that is filled in by the device-gated path — but it provides the bandwidth and footprint accounting that callers use to decide whether compression is worthwhile.

The compression ratio is defined as physical / effective: a ratio of 2.0 means the data occupies half its physical footprint over the memory bus, doubling effective bandwidth for that region.

Implementations

impl CompressedDeviceBuffer

pub fn new(plan: CompressionPlan) -> Self

Creates a descriptor for a freshly planned compressed buffer.

The compression ratio starts at 1.0 (no measured compression yet).

pub fn alloc( requested_bytes: usize, support: CompressionSupport, ) -> CudaResult<Self>

Builds a descriptor directly from a request, applying capability gating and granularity alignment in one step.

Errors

Forwards errors from CompressionPlan::new.

pub fn plan(&self) -> CompressionPlan

Returns the underlying allocation plan.

pub fn compression_type(&self) -> CompressionType

Returns the compression type recorded for this buffer.

pub fn logical_bytes(&self) -> usize

The logical (requested) size in bytes.

pub fn physical_bytes(&self) -> usize

The physical (granularity-aligned) footprint in bytes.

pub fn set_ratio(&mut self, ratio: f64)

Records an observed compression ratio (physical / effective).

Values below 1.0 are clamped to 1.0 (data cannot expand under lossless compression as far as bus traffic is concerned). Non-finite inputs are ignored.

pub fn ratio(&self) -> f64

Returns the recorded compression ratio (>= 1.0).

pub fn effective_bus_bytes(&self) -> usize

The effective number of bytes that traverse the memory bus given the recorded compression ratio.

Equal to physical_bytes / ratio, rounded down. With a ratio of 1.0 this equals the physical footprint.

pub fn effective_bandwidth_gbps(&self, dram_gbps: f64) -> f64

Estimates the effective bandwidth seen by a transfer of this buffer’s physical footprint, given a raw dram_gbps DRAM bandwidth.

Because compression reduces bus traffic by ratio, the effective bandwidth observed for compressible data is dram_gbps * ratio. Non-positive bandwidth returns 0.0.

pub fn bytes_saved(&self) -> usize

The number of physical bytes saved on the bus relative to an uncompressed transfer (physical - effective).

Trait Implementations

impl Clone for CompressedDeviceBuffer

fn clone(&self) -> CompressedDeviceBuffer

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CompressedDeviceBuffer

impl Debug for CompressedDeviceBuffer

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

Formats the value using the given formatter.

impl Display for CompressedDeviceBuffer

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

Formats the value using the given formatter.

impl PartialEq for CompressedDeviceBuffer

fn eq(&self, other: &CompressedDeviceBuffer) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for CompressedDeviceBuffer