mirror of
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
synced 2025-10-14 05:11:19 -04:00
839d221883
This design is easier to misuse, because it allows the caller to modify the contents of the slice after queueing it, but it avoids an extra allocation + memmove per incoming packet. Before: $ go test -bench='Benchmark(QueueIncoming|WriteTo)' -benchtime=2s -benchmem BenchmarkQueueIncoming-4 7001494 342.4 ns/op 1024 B/op 2 allocs/op BenchmarkWriteTo-4 3777459 627 ns/op 1024 B/op 2 allocs/op After: $ go test -bench=BenchmarkWriteTo -benchtime 2s -benchmem BenchmarkQueueIncoming-4 13361600 170.1 ns/op 512 B/op 1 allocs/op BenchmarkWriteTo-4 6702324 373 ns/op 512 B/op 1 allocs/op Despite the benchmark results, the change in QueueIncoming turns out not to have an effect in practice. It appears that the compiler had already been optimizing out the allocation and copy in QueueIncoming. https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40187 The WriteTo change, on the other hand, in practice reduces the frequency of garbage collection. https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40199
43 lines
995 B
Go
43 lines
995 B
Go
package turbotunnel
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import (
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"testing"
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"time"
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)
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type emptyAddr struct{}
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func (_ emptyAddr) Network() string { return "empty" }
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func (_ emptyAddr) String() string { return "empty" }
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// Run with -benchmem to see memory allocations.
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func BenchmarkQueueIncoming(b *testing.B) {
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conn := NewQueuePacketConn(emptyAddr{}, 1*time.Hour)
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defer conn.Close()
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b.ResetTimer()
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s := 500
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for i := 0; i < b.N; i++ {
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// Use a variable for the length to stop the compiler from
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// optimizing out the allocation.
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p := make([]byte, s)
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conn.QueueIncoming(p, emptyAddr{})
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}
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b.StopTimer()
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}
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// BenchmarkWriteTo benchmarks the QueuePacketConn.WriteTo function.
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func BenchmarkWriteTo(b *testing.B) {
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conn := NewQueuePacketConn(emptyAddr{}, 1*time.Hour)
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defer conn.Close()
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b.ResetTimer()
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s := 500
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for i := 0; i < b.N; i++ {
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// Use a variable for the length to stop the compiler from
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// optimizing out the allocation.
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p := make([]byte, s)
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conn.WriteTo(p, emptyAddr{})
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}
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b.StopTimer()
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}
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