chiwawa(CHeckpoint/restore and Instrumentation-specific WAsm runtime on WAsm runtime)

Chiwawa (Japanese-like Pronunciation of chihuahua) is a self-hosted Wasm runtime that enables live migration and instrumentation that is neutral to the execution methods (e.g., interpreter, JIT, and AOT) and architectures, and runtimes.

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Build and Run

cargo build --target wasm32-wasip1 --release

# Call function with Wasm parameters (I32, I64, F32, F64)
somethingWasmRuntime target/wasm32-wasip1/release/chiwawa.wasm test.wasm --invoke func-name --params "I64(100)"

# Pass command-line arguments to WASI-compiled program
somethingWasmRuntime target/wasm32-wasip1/release/chiwawa.wasm test.wasm --app-args "--version"

Checkpoint and Restore

Note: The checkpoint trigger mechanism differs between build targets:

• wasm32-wasip1-threads: Uses a background thread to monitor checkpoint.trigger file (recommended for better performance)
• wasm32-wasip1: Checks file existence via WASI at each instruction (use if host runtime does not support WASI threads)

cargo build --target wasm32-wasip1-threads --release

# Run with checkpoint enabled
somethingWasmRuntime target/wasm32-wasip1-threads/release/chiwawa.wasm test.wasm --invoke func-name --params "I64(100)" --cr
touch ./checkpoint.trigger # Trigger of Checkpointing
# Restore from checkpoint
somethingWasmRuntime target/wasm32-wasip1-threads/release/chiwawa.wasm test.wasm --restore checkpoint.bin

Tracing

Tracing requires the trace feature to be enabled at compile time:

# Build with trace feature
cargo build --target wasm32-wasip1 --release --features trace

# TRACE_EVENTS = (all,store,load,call,branch)
# TRACE_RESOURCE = (regs,memory,locals,globals,pc)
somethingWasmRuntime target/wasm32-wasip1/release/chiwawa.wasm test.wasm --trace --trace-events [<TRACE_EVENTS>...] --trace-resource [<TRACE_RESOURCE>...]

If --trace is used without the feature enabled, a warning is displayed and the flag is ignored.

Statistics

Statistics output requires the stats feature to be enabled at compile time:

# Build with stats feature
cargo build --target wasm32-wasip1 --release --features stats

# Run with statistics output
somethingWasmRuntime target/wasm32-wasip1/release/chiwawa.wasm test.wasm --stats

If --stats is used without the feature enabled, a warning is displayed and the flag is ignored.

Artifacts

Academic

• Y. Nakata and K. Matsubara, Self-Hosted WebAssembly Runtime for Runtime-Neutral Checkpoint/Restore in Edge–Cloud Continuum
  • The 3rd International Workshop on Middleware for the Computing Continuum (Mid4CC, 26th ACM/IFIP International Middleware Conference Co-located Workshop)
• Y. Nakata and K. Matsubara, Feasibility of Runtime-Neutral Wasm Instrumentation for Edge-Cloud Workload Handover
  • The Ninth ACM/IEEE Symposium on Edge Computing (SEC)

Tech Community

• Y.Nakata, What If the Runtime Was Portable Too? Self-Hosted Runtime Capabilities in Wasm
  • WasmCon NA (KubeCon + CloudNativeCon NA 2025 Co-located)
• Y. Nakata and D. Fujii, Beyond Portability: Live Migration for Evolving WebAssembly Workloads
  • Japan Community Day at KubeCon + CloudNativeCon Japan 2025

References

I referred to these repositories for initial implementation. I appreciate ancestor's wisdom!

• Wasm-rs
  • GitHub Repo
  • Article (Japanese)
• chibiwasm
  • GitHub Repo