etime

etime

etime extend golang's time package, to provide more and better features.

Install

go get github.com/go-eden/common/etime

Usage

This section shows all features, and their usage.

Current Timestamp

This feature works like Java's System.currentTimeMillis(), it will return int64 value directly:

• NowSecond: obtains the current second, use syscall for better performance
• NowMillisecond: obtains the current microsecond, use syscall for better performance
• NowMicrosecond: obtains the current millisecond, use syscall for better performance

For better performance, Now* didn't use time.Now(), because it's a bit slow.

Demo

package main

import (
	"github.com/go-eden/common/etime"
	"time"
)

func main() {
	println(etime.NowSecond())
	println(etime.NowMillisecond())
	println(etime.NowMicrosecond())

	println(time.Now().Unix())
	println(time.Now().UnixNano() / 1e6)
	println(time.Now().UnixNano() / 1e3)
}

Performance

In my benchmark, the performance of etime.NowSecond was about 40 ns/op, the performance of time.Now() was about 68 ns/op:

BenchmarkNowSecond-12         	29296284	        39.8 ns/op	       0 B/op	       0 allocs/op
BenchmarkNowMillisecond-12    	29361312	        40.7 ns/op	       0 B/op	       0 allocs/op
BenchmarkNowMicrosecond-12    	29742286	        40.1 ns/op	       0 B/op	       0 allocs/op
BenchmarkTimeNow-12           	15010953	        70.0 ns/op	       0 B/op	       0 allocs/op

Under the same hardware environment, Java's System.currentTimeMillis() was like this:

Benchmark               Mode  Cnt   Score   Error  Units
TimestampBenchmark.now  avgt    9  25.697 ± 0.139  ns/op

Some library may be sensitive to this 28ns optimization, like slf4go.

By the way, System.currentTimeMillis()'s implementation was similar with etime.NowSecond:

jlong os::javaTimeMillis() {
  timeval time;
  int status = gettimeofday(&time, NULL);
  assert(status != -1, "bsd error");
  return jlong(time.tv_sec) * 1000  +  jlong(time.tv_usec / 1000);
}

So, there should have room for improvement.

License

MIT