Measuring time in Go Routines - go

Question

Measuring time around a function is easy in Go.
But what if you need to measure it 5000 times per second in parallel?
I'm referring to Correctly measure time duration in Go which contains great answers about how to measure time in Go.
What is the cost of using time.Now() 5000 times per second or more?
While it may depend on the underlying OS, let's consider on linux.

Answer 1

Time measurement depends on the programming language and its implementation, the operating system and its implementation, the hardware architecture, implementation, and speed, and so on.
You need to focus on facts, not speculation. In Go, start with some benchmarks. For example,
since_test.go:
package main
import (
"testing"
"time"
)
var now time.Time
func BenchmarkNow(b *testing.B) {
for N := 0; N < b.N; N++ {
now = time.Now()
}
}
var since time.Duration
var start time.Time
func BenchmarkSince(b *testing.B) {
for N := 0; N < b.N; N++ {
start = time.Now()
since = time.Since(start)
}
}
Output:
$ go test since_test.go -bench=. -benchtime=1s
goos: linux
goarch: amd64
BenchmarkNow-4 30000000 47.5 ns/op
BenchmarkSince-4 20000000 98.1 ns/op
PASS
ok command-line-arguments 3.536s
$ go version
go version devel +48c4eeeed7 Sun Mar 25 08:33:21 2018 +0000 linux/amd64
$ uname -srvio
Linux 4.13.0-37-generic #42-Ubuntu SMP Wed Mar 7 14:13:23 UTC 2018 x86_64 GNU/Linux
$ cat /proc/cpuinfo | grep 'model name' | uniq
model name : Intel(R) Core(TM) i7-7500U CPU # 2.70GHz
$
Now, ask yourself if 5,000 times per second is necessary, practical, and reasonable.
What are your benchmark results?