perf: split delAllArgs into delAllArgs and delAllArgsStable

[ksw2000]

The original delAllArgs method is stable but requires more copying operations to maintain the order of elements.

• Renamed the original delAllArgs method to delAllArgsStable to maintain stable behavior.
• Added a new delAllArgs method for non-stable functionality, improving runtime efficiency.

Depending on the specific use case:

• Use delAllArgsStable when stability (order preservation) is required.
• Use delAllArgs when stability is not necessary.

In the case of handling headers in h.h, the order of headers is not important. Refer to net/http header.go, where the Del function calls textproto.MIMEHeader.Del. This function is implemented using a map, and the map delete operation is inherently unstable.

Benchmark compare delAllArgsStable and delAllArgs

func BenchmarkArgsDel(b *testing.B) {
	for i := 0; i < b.N; i++ {
		b.StopTimer()
		var a []argsKV
		for j := 1; j < 10; j++ {
			a = appendArg(a, fmt.Sprintf("item%d", j), "val", argsHasValue)
		}
		for j := 1; j < 10; j++ {
			a = appendArg(a, fmt.Sprintf("item%d", j), "val", argsHasValue)
		}
		b.StartTimer()
		for j := 1; j < 10; j++ {
			a = delAllArgs(a, fmt.Sprintf("item%d", j))
		}
	}
}

func BenchmarkArgsDelStable(b *testing.B) {
	for i := 0; i < b.N; i++ {
		b.StopTimer()
		var a []argsKV
		for j := 1; j < 10; j++ {
			a = appendArg(a, fmt.Sprintf("item%d", j), "val", argsHasValue)
		}
		for j := 1; j < 10; j++ {
			a = appendArg(a, fmt.Sprintf("item%d", j), "val", argsHasValue)
		}
		b.StartTimer()
		for j := 1; j < 10; j++ {
			a = delAllArgsStable(a, fmt.Sprintf("item%d", j))
		}
	}
}

Benchmark result:

$ go test --run=^$ --bench BenchmarkArgsDel -benchtime=100000x
goos: linux
goarch: amd64
pkg: github.com/valyala/fasthttp
cpu: AMD EPYC 7763 64-Core Processor                
BenchmarkArgsDel-4                100000              2072 ns/op
BenchmarkArgsDelStable-4          100000              2370 ns/op
PASS
ok      github.com/valyala/fasthttp     8.312s

[ksw2000]

@erikdubbelboer It's been 3 weeks, what do you think?

[erikdubbelboer]

Thanks I somehow missed it.