Avoid reallocating map in MatchLabels#10715
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roidelapluie merged 1 commit intoprometheus:mainfrom May 20, 2022
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We know the max size of our map so we can create it with that information and avoid extra allocations Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
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I've benchmarked it with: func BenchmarkLabels_MatchLabels(b *testing.B) {
maxLabels := 30
allLabels := make(Labels, maxLabels)
allNames := [][]string{}
for i := 0; i < maxLabels; i++ {
allLabels[i] = Label{Name: strings.Repeat(string('a'+byte(i)), 5)}
if i%5 == 0 || i == maxLabels-1 {
names := []string{}
for j := 0; j <= i; j++ {
names = append(names, allLabels[j].Name)
}
allNames = append(allNames, names)
names = names[:0]
for j := 0; j <= i; j++ {
names = append(names, allLabels[j].Name+"_miss")
}
allNames = append(allNames, names)
}
}
for _, size := range []int{5, 10, maxLabels} {
labels := allLabels[:size]
for _, on := range []bool{true, false} {
for _, names := range allNames {
b.Run(fmt.Sprintf("with %d labels on=%v names=%d", size, on, len(names)), func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
labels.MatchLabels(on, names...)
}
})
}
}
}
}But wasn't sure if that's a useful benchmark so didn't add it. Diff is below. benchstat diff |
roidelapluie
approved these changes
May 20, 2022
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I don't expect this to make a visible difference, but it's good to have it. |
roidelapluie
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Jun 22, 2022
We know the max size of our map so we can create it with that information and avoid extra allocations Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
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We know the max size of our map so we can create it with that information and avoid extra allocations
Signed-off-by: Łukasz Mierzwa l.mierzwa@gmail.com