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 (AMD Ryzen™ 5 2600).
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
Benchmark | Iteration time | Relative performance | Overhead |
---|---|---|---|
rand_napi | 569 ns | x1.00 | (ref) |
rand_koffi | 855 ns | x0.67 | +50% |
rand_node_ffi | 58730 ns | x0.010 | +10228% |
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.
Benchmark | Iteration time | Relative performance | Overhead |
---|---|---|---|
atoi_napi | 1039 ns | x1.00 | (ref) |
atoi_koffi | 1642 ns | x0.63 | +58% |
atoi_node_ffi | 164790 ns | x0.006 | +15767% |
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
Benchmark | Iteration time | Relative performance | Overhead |
---|---|---|---|
raylib_cc | 17.5 µs | x1.34 | -25% |
raylib_node_raylib | 23.4 µs | x1.00 | (ref) |
raylib_koffi | 28.8 µs | x0.81 | +23% |
raylib_node_ffi | 103.9 µs | x0.23 | +344% |
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
Benchmark | Iteration time | Relative performance | Overhead |
---|---|---|---|
rand_napi | 859 ns | x1.00 | (ref) |
rand_koffi | 1352 ns | x0.64 | +57% |
rand_node_ffi | 35640 ns | x0.02 | +4048% |
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):
Benchmark | Iteration time | Relative performance | Overhead |
---|---|---|---|
atoi_napi | 1336 ns | x1.00 | (ref) |
atoi_koffi | 2440 ns | x0.55 | +83% |
atoi_node_ffi | 136890 ns | x0.010 | +10144% |
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
Benchmark | Iteration time | Relative performance | Overhead |
---|---|---|---|
raylib_cc | 18.2 µs | x1.50 | -33% |
raylib_node_raylib | 27.3 µs | x1.00 | (ref) |
raylib_koffi | 29.8 µs | x0.92 | +9% |
raylib_node_ffi | 96.3 µs | x0.28 | +253% |
Running benchmarks
Please note that all benchmark results on this page are made with Clang-built binaries.
cd koffi
node ../../cnoke/cnoke.js --prefer-clang
cd koffi/benchmark
node ../../cnoke/cnoke.js --prefer-clang
Once everything is built and ready, run:
node benchmark.js