log/slog: use plain string concatenation for Attr.String
Plain string concatenation with the plus operator for Attr.String is
much faster than invoking fmt.Sprintf. Added a benchmark to verify
this (just running on my Mac with stuff in the background but should
be sufficient to demonstrate the effect).
name old time/op new time/op delta
AttrString-8 1.24µs ± 3% 0.43µs ± 0% -65.17% (p=0.000 n=20+17)
name old alloc/op new alloc/op delta
AttrString-8 432B ± 0% 152B ± 0% ~ (p=1.000 n=1+1)
name old allocs/op new allocs/op delta
AttrString-8 30.0 ± 0% 16.0 ± 0% ~ (p=1.000 n=1+1)
Change-Id: I18ac91cbff1047d168b51a595601e36b5f676615
Reviewed-on: https://go-review.googlesource.com/c/go/+/573517 Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
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Auto-Submit: Emmanuel Odeke <emmanuel@orijtech.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
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