Struct ControlBlock 

#[repr(C, align(128))]
pub struct ControlBlock {

    pub is_active: u32,
    pub should_terminate: u32,
    pub has_terminated: u32,
    pub _pad1: u32,
    pub messages_processed: u64,
    pub messages_in_flight: u64,
    pub input_head: u64,
    pub input_tail: u64,
    pub output_head: u64,
    pub output_tail: u64,
    pub input_capacity: u32,
    pub output_capacity: u32,
    pub input_mask: u32,
    pub output_mask: u32,
    pub hlc_state: HlcState,
    pub last_error: u32,
    pub error_count: u32,
    pub _reserved: [u8; 24],
}

Kernel control block (128 bytes, cache-line aligned).

This structure resides in GPU global memory and is accessed atomically by both host and device code for kernel lifecycle management.

Memory Layout

The structure is carefully designed to minimize false sharing:

• Frequently written fields are grouped together
• Read-only fields are separated
• Padding ensures proper alignment

Fields

is_active: u32

Kernel is actively processing messages (atomic bool).

should_terminate: u32

Signal to terminate the kernel (atomic bool).

has_terminated: u32

Kernel has completed termination (atomic bool).

_pad1: u32

Reserved for alignment.

messages_processed: u64

Total messages processed.

messages_in_flight: u64

Messages currently being processed.

input_head: u64

Input queue head pointer (producer writes).

input_tail: u64

Input queue tail pointer (consumer reads).

output_head: u64

Output queue head pointer (producer writes).

output_tail: u64

Output queue tail pointer (consumer reads).

input_capacity: u32

Input queue capacity (power of 2).

output_capacity: u32

Output queue capacity (power of 2).

input_mask: u32

Input queue mask (capacity - 1).

output_mask: u32

Output queue mask (capacity - 1).

hlc_state: HlcState

HLC state for this kernel.

last_error: u32

Last error code (0 = no error).

error_count: u32

Error count.

_reserved: [u8; 24]

Reserved for future use.

Implementations

impl ControlBlock

pub const fn new() -> Self

Create a new control block with default values.

pub fn with_capacities(input_capacity: u32, output_capacity: u32) -> Self

Create with specified queue capacities.

Capacities must be powers of 2.

pub fn is_active(&self) -> bool

Check if the kernel is active.

pub fn should_terminate(&self) -> bool

Check if termination was requested.

pub fn has_terminated(&self) -> bool

Check if the kernel has terminated.

pub fn input_queue_size(&self) -> u64

Get input queue size.

pub fn output_queue_size(&self) -> u64

Get output queue size.

pub fn input_queue_empty(&self) -> bool

Check if input queue is empty.

pub fn output_queue_empty(&self) -> bool

Check if output queue is empty.

pub fn input_queue_full(&self) -> bool

Check if input queue is full.

pub fn output_queue_full(&self) -> bool

Check if output queue is full.

Trait Implementations

impl Clone for ControlBlock

fn clone(&self) -> ControlBlock

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ControlBlock

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

Formats the value using the given formatter.

impl Default for ControlBlock

fn default() -> Self

Returns the “default value” for a type.

impl Copy for ControlBlock