According to static analysis of Go source code known by the module proxy,
spaces, dashes, zeros, and tabs are the most commonly repeated string literals.
Out of ~69k total calls to Repeat:
* ~25k calls are repeats of " "
* ~7k calls are repeats of "-"
* ~4k calls are repeats of "0"
* ~2k calls are repeats of "="
* ~2k calls are repeats of "\t"
After this optimization, ~60% of Repeat calls will go through the fast path.
These are often used in padding of fixed-width terminal UI or
in the presentation of humanly readable text
(e.g., indentation made of spaces or tabs).
Optimize for this case by handling short repeated sequences of common literals.
Performance:
name old time/op new time/op delta
RepeatSpaces-24 19.3ns ± 1% 5.0ns ± 1% -74.27% (p=0.000 n=8+9)
name old alloc/op new alloc/op delta
RepeatSpaces-24 2.00B ± 0% 0.00B -100.00% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
RepeatSpaces-24 1.00 ± 0% 0.00 -100.00% (p=0.000 n=10+10)
Change-Id: Id1cafd0cc509e835c8241a626489eb206e0adc3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/536615 Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com> Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>