Simple benchmark for three logging packages.

logfmt-bench_test.go

package main

import (
	"io/ioutil"
	"testing"

	"github.com/Sirupsen/logrus"
	"github.com/go-kit/kit/log"
	"gopkg.in/inconshreveable/log15.v2"
)

func BenchmarkGokitLogfmt(b *testing.B) {
	lg := log.NewLogfmtLogger(ioutil.Discard)
	for i := 0; i < b.N; i++ {
		lg.Log("lvl", "info", "msg", "test message", "k1", "v1", "k2", "v2", "k3", "v3")
	}
}

func BenchmarkLog15Logfmt(b *testing.B) {
	lg := log15.New()
	lg.SetHandler(log15.StreamHandler(ioutil.Discard, log15.LogfmtFormat()))

	for i := 0; i < b.N; i++ {
		lg.Info("test message", "k1", "v1", "k2", "v2", "k3", "v3")
	}
}

func BenchmarkLogrusLogfmt(b *testing.B) {
	lg := logrus.New()
	lg.Out = ioutil.Discard

	for i := 0; i < b.N; i++ {
		lg.WithFields(logrus.Fields{
			"k1": "v1", "k2": "v2", "k3": "v3",
		}).Info("test message")
	}
}

GokitLogfmt has improved since the first posting. Here are updated benchmarks for Go 1.6.2 on the same machine as before with the latest versions of all the packages. This time using benchstat with 10 runs.

name            time/op
GokitLogfmt-4   3.60µs ± 3%
Log15Logfmt-4   18.2µs ± 1%
LogrusLogfmt-4  12.7µs ± 1%

name            alloc/op
GokitLogfmt-4     432B ± 0%
Log15Logfmt-4   1.96kB ± 0%
LogrusLogfmt-4  1.62kB ± 0%

name            allocs/op
GokitLogfmt-4     12.0 ± 0%
Log15Logfmt-4     45.0 ± 0%
LogrusLogfmt-4    27.0 ± 0%

Another performance improvement in GokitLogfmt: Less memory allocation when handling values that require quoting.

name            time/op
GokitLogfmt-4   3.41µs ± 3%
Log15Logfmt-4   18.4µs ± 4%
LogrusLogfmt-4  12.8µs ± 1%

name            alloc/op
GokitLogfmt-4     320B ± 0%
Log15Logfmt-4   1.96kB ± 0%
LogrusLogfmt-4  1.62kB ± 0%

name            allocs/op
GokitLogfmt-4     11.0 ± 0%
Log15Logfmt-4     45.0 ± 0%
LogrusLogfmt-4    27.0 ± 0%