prometheus/pkg/labels/matcher_test.go
Oleg Zaytsev 280eaf33f0
Use global string map for MatchType.String() (#9237)
* Use global string map for MatchType.String()

We were unnecessarily creating a new map for each call of String().

This is a 10x improvement in MatchType.String() performance in time,
from 53ns to 4ns on my i7 laptop, and I guess that this method is being
called quite often so why throw out the resources.

I was surprised that benchmark says that there are no allocations made
in the old version.

I also tries using `//go:generate stringer` and the result is even
better, at about 2.8ns, but having to keep the generated code updated
isn't worth the change (at least it's bigger than a small change I was
intended to do)

Benchmark comparison:

    name \ time/op    old          global_map  stringer
    MatchType_String  53.6ns ± 1%  4.1ns ± 1%  2.8ns ± 1%

    name \ alloc/op   old          global_map  stringer
    MatchType_String   0.00B       0.00B       0.00B

    name \ allocs/op  old          global_map  stringer
    MatchType_String    0.00        0.00        0.00

Old benchmark:

    goos: darwin
    goarch: amd64
    pkg: github.com/prometheus/prometheus/pkg/labels
    cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    BenchmarkMatchType_String 	21766578	        54.36 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	21742339	        53.28 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	21985470	        53.37 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	21676282	        53.50 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	22075573	        53.33 ns/op	       0 B/op	       0 allocs/op
    PASS
    ok  	github.com/prometheus/prometheus/pkg/labels	6.252s

New with global map:

    goos: darwin
    goarch: amd64
    pkg: github.com/prometheus/prometheus/pkg/labels
    cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    BenchmarkMatchType_String 	283412692	         4.129 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	294859941	         4.091 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	295750158	         4.113 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	282827982	         4.072 ns/op	       0 B/op	       0 allocs/op
    BenchmarkMatchType_String 	292942393	         4.047 ns/op	       0 B/op	       0 allocs/op
    PASS
    ok  	github.com/prometheus/prometheus/pkg/labels	8.238s

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use array instead of map

Since MatchType is an iota type, we can safely use an array here.

This solution is even better:

    name \ time/op    old          global_map  stringer    array
    MatchType_String  53.6ns ± 1%  4.1ns ± 1%  2.8ns ± 1%  1.0ns ± 1%

    name \ alloc/op   old          global_map  stringer    array
    MatchType_String   0.00B       0.00B       0.00B       0.00B

    name \ allocs/op  old          global_map  stringer    array
    MatchType_String    0.00        0.00        0.00        0.00

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Benchmark all MatchType values

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use constants for limits

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-08-24 11:26:16 +05:30

126 lines
3.0 KiB
Go

// Copyright 2017 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package labels
import (
"testing"
"github.com/stretchr/testify/require"
)
func mustNewMatcher(t *testing.T, mType MatchType, value string) *Matcher {
m, err := NewMatcher(mType, "", value)
require.NoError(t, err)
return m
}
func TestMatcher(t *testing.T) {
tests := []struct {
matcher *Matcher
value string
match bool
}{
{
matcher: mustNewMatcher(t, MatchEqual, "bar"),
value: "bar",
match: true,
},
{
matcher: mustNewMatcher(t, MatchEqual, "bar"),
value: "foo-bar",
match: false,
},
{
matcher: mustNewMatcher(t, MatchNotEqual, "bar"),
value: "bar",
match: false,
},
{
matcher: mustNewMatcher(t, MatchNotEqual, "bar"),
value: "foo-bar",
match: true,
},
{
matcher: mustNewMatcher(t, MatchRegexp, "bar"),
value: "bar",
match: true,
},
{
matcher: mustNewMatcher(t, MatchRegexp, "bar"),
value: "foo-bar",
match: false,
},
{
matcher: mustNewMatcher(t, MatchRegexp, ".*bar"),
value: "foo-bar",
match: true,
},
{
matcher: mustNewMatcher(t, MatchNotRegexp, "bar"),
value: "bar",
match: false,
},
{
matcher: mustNewMatcher(t, MatchNotRegexp, "bar"),
value: "foo-bar",
match: true,
},
{
matcher: mustNewMatcher(t, MatchNotRegexp, ".*bar"),
value: "foo-bar",
match: false,
},
}
for _, test := range tests {
require.Equal(t, test.matcher.Matches(test.value), test.match)
}
}
func TestInverse(t *testing.T) {
tests := []struct {
matcher *Matcher
expected *Matcher
}{
{
matcher: &Matcher{Type: MatchEqual, Name: "name1", Value: "value1"},
expected: &Matcher{Type: MatchNotEqual, Name: "name1", Value: "value1"},
},
{
matcher: &Matcher{Type: MatchNotEqual, Name: "name2", Value: "value2"},
expected: &Matcher{Type: MatchEqual, Name: "name2", Value: "value2"},
},
{
matcher: &Matcher{Type: MatchRegexp, Name: "name3", Value: "value3"},
expected: &Matcher{Type: MatchNotRegexp, Name: "name3", Value: "value3"},
},
{
matcher: &Matcher{Type: MatchNotRegexp, Name: "name4", Value: "value4"},
expected: &Matcher{Type: MatchRegexp, Name: "name4", Value: "value4"},
},
}
for _, test := range tests {
result, err := test.matcher.Inverse()
require.NoError(t, err)
require.Equal(t, test.expected.Type, result.Type)
}
}
func BenchmarkMatchType_String(b *testing.B) {
for i := 0; i <= b.N; i++ {
_ = MatchType(i % int(MatchNotRegexp+1)).String()
}
}