strings: add Builder benchmarks comparing bytes.Buffer and strings.Builder
Despite the existing test that locks in the allocation behavior, people
really want a benchmark. So:
BenchmarkBuildString_Builder/1Write_NoGrow-4
20000000 60.4 ns/op 48 B/op 1 allocs/op
BenchmarkBuildString_Builder/3Write_NoGrow-4
10000000 230 ns/op 336 B/op 3 allocs/op
BenchmarkBuildString_Builder/3Write_Grow-4
20000000 102 ns/op 112 B/op 1 allocs/op
BenchmarkBuildString_ByteBuffer/1Write_NoGrow-4
10000000 125 ns/op 160 B/op 2 allocs/op
BenchmarkBuildString_ByteBuffer/3Write_NoGrow-4
5000000 339 ns/op 400 B/op 3 allocs/op
BenchmarkBuildString_ByteBuffer/3Write_Grow-4
5000000 316 ns/op 336 B/op 3 allocs/op
I don't think these allocate-as-fast-as-you-can benchmarks are very
interesting because they're effectively just GC benchmarks, but sure.
If one wants to see that there's 1 fewer allocation, there it is. The
ns/op and B/op numbers will change as the built string size changes.
Updates #18990
Change-Id: Ifccf535bd396217434a0e6989e195105f90132ae
Reviewed-on: https://go-review.googlesource.com/96980
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>