Overview

Here is a quick overview of the execution time of Koffi calls on three benchmarks, where it is compared to a theoretical ideal FFI implementation (approximated with pre-compiled static N-API glue code):

• The first benchmark is based on rand() calls
• The second benchmark is based on atoi() calls
• The third benchmark is based on Raylib

These results are detailed and explained below, and compared to node-ffi/node-ffi-napi.

Linux x86_64

The results presented below were measured on my x86_64 Linux machine (Intel® Core™ Ultra 9 185H).

rand results

This test is based around repeated calls to a simple standard C function rand, and has three implementations:

• the first one is the reference, it calls rand through an N-API module, and is close to the theoretical limit of a perfect (no overhead) Node.js > C FFI implementation (pre-compiled static glue code)
• the second one calls rand through Koffi
• the third one uses the official Node.js FFI implementation, node-ffi-napi

Because rand is a pretty small function, the FFI overhead is clearly visible.

atoi results

This test is similar to the rand one, but it is based on atoi, which takes a string parameter. Javascript (V8) to C string conversion is relatively slow and heavy.

Because atoi is a pretty small function, the FFI overhead is clearly visible.

Raylib results

This benchmark uses the CPU-based image drawing functions in Raylib. The calls are much heavier than in previous benchmarks, thus the FFI overhead is reduced. In this implementation, Koffi is compared to:

• Baseline: Full C++ version of the code (no JS)
• node-raylib: This is a native wrapper implemented with N-API

Windows x86_64

The results presented below were measured on my x86_64 Windows machine (Intel® Core™ i5-4460).

rand results

This test is based around repeated calls to a simple standard C function rand, and has three implementations:

• the first one is the reference, it calls rand through an N-API module, and is close to the theoretical limit of a perfect (no overhead) Node.js > C FFI implementation (pre-compiled static glue code)
• the second one calls rand through Koffi
• the third one uses the official Node.js FFI implementation, node-ffi-napi

Because rand is a pretty small function, the FFI overhead is clearly visible.

atoi results

This test is similar to the rand one, but it is based on atoi, which takes a string parameter. Javascript (V8) to C string conversion is relatively slow and heavy.

The results below were measured on my x86_64 Windows machine (Intel® Core™ i5-4460):

Because atoi is a pretty small function, the FFI overhead is clearly visible.

Raylib results

This benchmark uses the CPU-based image drawing functions in Raylib. The calls are much heavier than in the atoi benchmark, thus the FFI overhead is reduced. In this implementation, Koffi is compared to:

• node-raylib (baseline): This is a native wrapper implemented with N-API
• raylib_cc: C++ implementation of the benchmark, without any Javascript

Running benchmarks

Please note that all benchmark results on this page are made with Clang-built binaries.

cd src/koffi
node ../cnoke/cnoke.js --clang --release

cd benchmark
node ../../cnoke/cnoke.js --clang --release

Once everything is built and ready, run:

node benchmark.js