From 4baa486983204fdff64f80809627f79a538d8d82 Mon Sep 17 00:00:00 2001 From: Emmanuel T Odeke Date: Fri, 9 Sep 2022 09:59:21 -0700 Subject: all: remove unnecessary allocations from w.WriteString(fmt.Sprint*(...)) by fmt.Fprint*(w, ...) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Noticed in a manual audit from a customer codebase that the pattern w.WriteString(fmt.Sprint*(args...)) was less efficient and in most cases we can just invoke: fmt.Fprint*(w, args...) and from the simple benchmarks we can see quick wins in all dimensions: $ benchstat before.txt after.txt name old time/op new time/op delta DetailString-8 5.48µs ±23% 4.40µs ±11% -19.79% (p=0.000 n=20+17) name old alloc/op new alloc/op delta DetailString-8 2.63kB ± 0% 2.11kB ± 0% -19.76% (p=0.000 n=20+20) name old allocs/op new allocs/op delta DetailString-8 63.0 ± 0% 50.0 ± 0% -20.63% (p=0.000 n=20+20) Change-Id: I47a2827cd34d6b92644900b1bd5f4c0a3287bdb1 Reviewed-on: https://go-review.googlesource.com/c/go/+/429861 Reviewed-by: Robert Findley Reviewed-by: hopehook Reviewed-by: Ian Lance Taylor Run-TryBot: Emmanuel Odeke TryBot-Result: Gopher Robot Reviewed-by: Daniel Martí --- src/cmd/compile/internal/syntax/scanner_test.go | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/cmd/compile/internal/syntax') diff --git a/src/cmd/compile/internal/syntax/scanner_test.go b/src/cmd/compile/internal/syntax/scanner_test.go index 2deb3bbf84..450ec1ff8a 100644 --- a/src/cmd/compile/internal/syntax/scanner_test.go +++ b/src/cmd/compile/internal/syntax/scanner_test.go @@ -88,10 +88,10 @@ func TestEmbeddedTokens(t *testing.T) { // make source var buf bytes.Buffer for i, s := range sampleTokens { - buf.WriteString("\t\t\t\t"[:i&3]) // leading indentation - buf.WriteString(s.src) // token - buf.WriteString(" "[:i&7]) // trailing spaces - buf.WriteString(fmt.Sprintf("/*line foo:%d */ // bar\n", i)) // comments + newline (don't crash w/o directive handler) + buf.WriteString("\t\t\t\t"[:i&3]) // leading indentation + buf.WriteString(s.src) // token + buf.WriteString(" "[:i&7]) // trailing spaces + fmt.Fprintf(&buf, "/*line foo:%d */ // bar\n", i) // comments + newline (don't crash w/o directive handler) } // scan source -- cgit v1.3-5-g9baa