Benchmarking Go errors

How does creation, serialization, and wrapping changes with different errors?

Notation * fmt.Errorf you wrap like this fmt.Errorf("my message %s with data %f: %w", err) * DelayedError you wrap underlying error into field but do not call e.Err.Error() immediately * errors.New you create error with string passed directly into struct, no fmt calls made.

Results 1. fmt.Errorf wrapping calls Error immediately. Delaying Error call is not utilized 2. errors.New is very fast when no complex formatting (floats/reflection/iterables) is necessary 3. DelayedError is 10x faster when Error calls are not done, since Error calls are lazily delayed 4. Error call for fmt.Errorf and for DelayedError takes same time

Benchmarks $ go test -bench=. -benchtime=5s -benchmem ./... goos: darwin goarch: amd64 pkg: github.com/nikolaydubina/go-bench-errors cpu: VirtualApple @ 2.50GHz BenchmarkWrap_DelayedError_float64_Message_2wrap-10 14211424 419 ns/op 216 B/op 8 allocs/op BenchmarkWrap_DelayedError_float64_2wrap-10 99927066 58 ns/op 96 B/op 2 allocs/op BenchmarkWrap_DelayedError_float64_Message_5wrap-10 5403166 1097 ns/op 736 B/op 20 allocs/op BenchmarkWrap_DelayedError_float64_5wrap-10 38846422 153 ns/op 240 B/op 5 allocs/op BenchmarkWrap_DelayedError_float64_Message_10wrap-10 2672426 2246 ns/op 2072 B/op 40 allocs/op BenchmarkWrap_DelayedError_float64_10wrap-10 19889925 299 ns/op 480 B/op 10 allocs/op BenchmarkWrap_DelayedError_float64_Message_50wrap-10 394473 14857 ns/op 35814 B/op 200 allocs/op BenchmarkWrap_DelayedError_float64_50wrap-10 4079131 1467 ns/op 2400 B/op 50 allocs/op BenchmarkWrap_fmt_Errorf_float64_Message_2wrap-10 13853347 430 ns/op 176 B/op 6 allocs/op BenchmarkWrap_fmt_Errorf_float64_2wrap-10 13966632 429 ns/op 176 B/op 6 allocs/op BenchmarkWrap_fmt_Errorf_float64_Message_5wrap-10 5036449 1191 ns/op 664 B/op 15 allocs/op BenchmarkWrap_fmt_Errorf_float64_5wrap-10 5040122 1189 ns/op 664 B/op 15 allocs/op BenchmarkWrap_fmt_Errorf_float64_Message_10wrap-10 2418132 2485 ns/op 2048 B/op 30 allocs/op BenchmarkWrap_fmt_Errorf_float64_10wrap-10 2414413 2484 ns/op 2048 B/op 30 allocs/op BenchmarkWrap_fmt_Errorf_float64_Message_50wrap-10 353810 16856 ns/op 38867 B/op 150 allocs/op BenchmarkWrap_fmt_Errorf_float64_50wrap-10 353611 16808 ns/op 38867 B/op 150 allocs/op BenchmarkSingle_fmt_Errorf_float64_Message-10 27763376 215 ns/op 72 B/op 3 allocs/op BenchmarkSingle_fmt_Errorf_float64-10 30912550 192 ns/op 72 B/op 3 allocs/op BenchmarkSingle_fmt_Errorf_int_Message-10 46369344 129 ns/op 51 B/op 3 allocs/op BenchmarkSingle_fmt_Errorf_int-10 56102511 106 ns/op 51 B/op 3 allocs/op BenchmarkSingle_errors_New_int_Message-10 100000000 53 ns/op 4 B/op 1 allocs/op BenchmarkSingle_errors_New_int-10 163252323 36 ns/op 4 B/op 1 allocs/op PASS ok github.com/nikolaydubina/go-bench-errors 149.863s