Module checkpoint 

Kernel checkpointing for persistent state snapshot and restore.

This module provides infrastructure for checkpointing persistent GPU kernels, enabling fault tolerance, migration, and debugging capabilities.

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                    CheckpointableKernel                         │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────────────────┐  │
│  │ Control     │  │ Queue       │  │ Device Memory           │  │
│  │ Block       │  │ State       │  │ (pressure, halo, etc.)  │  │
│  └─────────────┘  └─────────────┘  └─────────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
                             │
                             ▼
┌─────────────────────────────────────────────────────────────────┐
│                        Checkpoint                               │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────────────────┐  │
│  │ Header      │  │ Metadata    │  │ Compressed Data Chunks  │  │
│  │ (magic,ver) │  │ (kernel_id) │  │ (control,queues,memory) │  │
│  └─────────────┘  └─────────────┘  └─────────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
                             │
                             ▼
┌─────────────────────────────────────────────────────────────────┐
│                   CheckpointStorage                             │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────────────────┐  │
│  │ File        │  │ Memory      │  │ Cloud (S3/GCS)          │  │
│  │ Backend     │  │ Backend     │  │ Backend                 │  │
│  └─────────────┘  └─────────────┘  └─────────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘

Example

use ringkernel_core::checkpoint::{Checkpoint, FileStorage, CheckpointableKernel};

// Create checkpoint from running kernel
let checkpoint = kernel.create_checkpoint()?;

// Save to file
let storage = FileStorage::new("/checkpoints");
storage.save(&checkpoint, "sim_step_1000")?;

// Later: restore from checkpoint
let checkpoint = storage.load("sim_step_1000")?;
kernel.restore_from_checkpoint(&checkpoint)?;

Structs

Checkpoint

Complete checkpoint containing all kernel state.

CheckpointBuilder

Builder for creating checkpoints incrementally.

CheckpointHeader

Checkpoint file header (64 bytes, fixed size).

CheckpointMetadata

Kernel-specific metadata stored in checkpoint.

ChunkHeader

Header for each data chunk (32 bytes).

DataChunk

A single data chunk in a checkpoint.

FileStorage

File-based checkpoint storage.

MemoryStorage

In-memory checkpoint storage (for testing and fast operations).

Enums

ChunkType

Chunk types for checkpoint data sections.

Constants

CHECKPOINT_MAGIC

Magic number for checkpoint files: “RKCKPT01” in ASCII.

CHECKPOINT_VERSION

Current checkpoint format version.

MAX_CHECKPOINT_SIZE

Maximum supported checkpoint size (1 GB).

Traits

CheckpointStorage

Trait for checkpoint storage backends.

CheckpointableKernel

Trait for kernels that support checkpointing.