node/benchmark/README.md

Node.js Core Benchmarks

This folder contains code and data used to measure performance of different Node.js implementations and different ways of writing JavaScript run by the built-in JavaScript engine.

For a detailed guide on how to write and run benchmarks in this directory, see the guide on benchmarks.

Table of Contents

• Benchmark directories
• Common API

Benchmark Directories

Directory	Purpose
arrays	Benchmarks for various operations on array-like objects, including Array, Buffer, and typed arrays.
assert	Benchmarks for the assert subsystem.
buffers	Benchmarks for the buffer subsystem.
child_process	Benchmarks for the child_process subsystem.
crypto	Benchmarks for the crypto subsystem.
dgram	Benchmarks for the dgram subsystem.
domain	Benchmarks for the domain subsystem.
es	Benchmarks for various new ECMAScript features and their pre-ES2015 counterparts.
events	Benchmarks for the events subsystem.
fixtures	Benchmarks fixtures used in various benchmarks throughout the benchmark suite.
fs	Benchmarks for the fs subsystem.
http	Benchmarks for the http subsystem.
misc	Miscellaneous benchmarks and benchmarks for shared internal modules.
module	Benchmarks for the module subsystem.
net	Benchmarks for the net subsystem.
path	Benchmarks for the path subsystem.
process	Benchmarks for the process subsystem.
querystring	Benchmarks for the querystring subsystem.
streams	Benchmarks for the streams subsystem.
string_decoder	Benchmarks for the string_decoder subsystem.
timers	Benchmarks for the timers subsystem, including setTimeout, setInterval, .etc.
tls	Benchmarks for the tls subsystem.
url	Benchmarks for the url subsystem, including the legacy url implementation and the WHATWG URL implementation.
util	Benchmarks for the util subsystem.
vm	Benchmarks for the vm subsystem.

Other Top-level files

The top-level files include common dependencies of the benchmarks and the tools for launching benchmarks and visualizing their output. The actual benchmark scripts should be placed in their corresponding directories.

• _benchmark_progress.js: implements the progress bar displayed when running compare.js
• _cli.js: parses the command line arguments passed to compare.js, run.js and scatter.js
• _cli.R: parses the command line arguments passed to compare.R
• _http-benchmarkers.js: selects and runs external tools for benchmarking the http subsystem.
• common.js: see Common API.
• compare.js: command line tool for comparing performance between different Node.js binaries.
• compare.R: R script for statistically analyzing the output of compare.js
• run.js: command line tool for running individual benchmark suite(s).
• scatter.js: command line tool for comparing the performance between different parameters in benchmark configurations, for example to analyze the time complexity.
• scatter.R: R script for visualizing the output of scatter.js with scatter plots.

Common API

The common.js module is used by benchmarks for consistency across repeated tasks. It has a number of helpful functions and properties to help with writing benchmarks.

createBenchmark(fn, configs[, options])

See the guide on writing benchmarks.

default_http_benchmarker

The default benchmarker used to run HTTP benchmarks. See the guide on writing HTTP benchmarks.

PORT

The default port used to run HTTP benchmarks. See the guide on writing HTTP benchmarks.

sendResult(data)

Used in special benchmarks that can't use createBenchmark and the object it returns to accomplish what they need. This function reports timing data to the parent process (usually created by running compare.js, run.js or scatter.js).

v8ForceOptimization(method[, ...args])

Force V8 to mark the method for optimization with the native function %OptimizeFunctionOnNextCall() and return the optimization status after that.

It can be used to prevent the benchmark from getting disrupted by the optimizer kicking in halfway through. However, this could result in a less effective optimization. In general, only use it if you know what it actually does.