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Go Lang Notes

Compilations of Go Lang sample code along with AWS examples. Topped with notes on related topics.

Execution Time in Go Lang

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In order to measure performance or benchmarking a go program you can measure it’s execution time.

Simple Code Logic for Execution Time

Below is a simple go code that measures its execution time.

import (
    "log"
    "time"
)

func main() {
    start := time.Now()
    // Your Code Logic....
    log.Println(time.Since(start))
}

In above code what we have done is recorded a start time. Then after the code logic is executed we are printing the elapsed time w.r.t the recorded start time.

Measuring Function Execution Time

In order to measure the execution time for a function in go lang, the easier way is to use defer and some shared code logic.

Shared Code Logic

// Track function return the message along with start time for the function/method
func Track(msg string) (string, time.Time) {
    return msg, time.Now()
}

// Duration function prints out the message along with time elapsed since start
func Duration(msg string, start time.Time) {
    log.Printf("%v: %v\n", msg, time.Since(start))
}

Implementation Code Logic

Now you can use the above shared code logic inside your function. Below is a sample code for reference. We use defer here since we want execution time to be calculated and displayed on end of the function/method execution

// SomeFunction is just a dummy sample function
func SomeFunction() {
    defer Duration(Track("SomeFunction"))
    time.Sleep(1 * time.Minute)
}

Benchmarking in Go Lang

Benchmarks are written in *_test.go file and the Benchmarking Methods start with Benchmark*.

For demo purpose you can use this code

Sample code looks like given below

package service

import (
    "testing"
)

func BenchmarkSampleFunction(b *testing.B) {
    for i := 0; i < b.N; i++ {
        SampleFunction()
    }
}

Instead of using go test, you can also call testing.Benchmark from a command

package main

import (
    "fmt"
    "testing"

    "github.com/aasisodiya/go/benchmark/service"
)

func BenchmarkSampleFunction(b *testing.B) {
    for i := 0; i < b.N; i++ {
        service.SampleFunction()
    }
}

func main() {
    fmt.Println(testing.Benchmark(BenchmarkSampleFunction))
}

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