9.4 Benchmark
Ruby
标准库的Benchmark
Benchmark.measure {code}Benchmark.bm(label_width = 0) {|job| job.report(label) {code} }可以有多个job.report， label可选Benchmark.bmbm(label_width)2次测试，第一次是演练，第二次是真实
示例:
require 'benchmark'
n = 100_000
size = 10_000
array = (0...size).to_a.shuffle
benchmark.bm do |x|
x.report("#at") {
n.times { array.at rand(size)}
}
x.report("#index") {
n.times { array.index rand(size) }
}
end
user system total real
#at 0.020000 0.000000 0.020000 ( 0.025401)
#index 3.060000 0.010000 3.070000 ( 3.062166)
输出四个时间分别是(单位是秒)：
user: the amount of time spent executing userspace code (i.e.: your code),
system: the amount of time spent executing kernel code
user + system
real: the "real" amount of time it took to execute the code (i.e. system + user + time spent waiting for I/O, network, disk, user input, etc.). Also known as "wallclock time".
benchmark/ips
https://github.com/evanphx/benchmark-ips
- 会计算一个合适的运算次数, 用以提供合理的比较结果, 结果通过每秒多少次进行展示
- 输出标准方差 (各数据偏离平均数的距离（离均差）的平均数)
- 比较功能
benchmark/bigo
https://github.com/davy/benchmark-bigo
- 不同大小样本下, 进行比较
- 图表比较功能(前端图表库ChartKick) 非常直观
- 终端输出ASCII 图表(需要安装gnuplot) 将就可用
参考: https://zhongfox.github.io/2015/11/30/ruby-benchmark/
Javascript
process.hrtime([time])
返回current high-resolution real time, 格式为[seconds, nanoseconds]
可选参数也是process.hrtime的上一个返回值, 如果传递将diff2个时间:
var time = process.hrtime();
// [ 1800216, 25 ]
setTimeout(() => {
var diff = process.hrtime(time);
// [ 1, 552 ]
console.log(`Benchmark took ${diff[0] * 1e9 + diff[1]} nanoseconds`);
// benchmark took 1000000527 nanoseconds
}, 1000);