From c6aa2e5ac8097f9491a407c3bb2385159d9aed32 Mon Sep 17 00:00:00 2001 From: Anthony Martin Date: Thu, 15 May 2014 20:12:06 -0700 Subject: [PATCH] cmd/pack: buffer writes in TestLargeDefs TestLargeDefs was issuing over one million small writes to create a 7MB file (large.go). This is quite slow on Plan 9 since our disk file systems aren't very fast and they're usually accessed over the network. Buffering the writes makes the test about six times faster. Even on Linux, it's about 1.5 times faster. Here are the results on a slow Plan 9 machine: Before: % ./pack.test -test.v -test.run TestLargeDefs === RUN TestLargeDefs --- PASS: TestLargeDefs (125.11 seconds) PASS After: % ./pack.test -test.v -test.run TestLargeDefs === RUN TestLargeDefs --- PASS: TestLargeDefs (20.835 seconds) PASS LGTM=iant R=golang-codereviews, iant CC=golang-codereviews https://golang.org/cl/95040044 --- src/cmd/pack/pack_test.go | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/cmd/pack/pack_test.go b/src/cmd/pack/pack_test.go index 8ecca98e63..e634c86f76 100644 --- a/src/cmd/pack/pack_test.go +++ b/src/cmd/pack/pack_test.go @@ -5,6 +5,7 @@ package main import ( + "bufio" "bytes" "fmt" "io" @@ -223,9 +224,10 @@ func TestLargeDefs(t *testing.T) { if err != nil { t.Fatal(err) } + b := bufio.NewWriter(f) printf := func(format string, args ...interface{}) { - _, err := fmt.Fprintf(f, format, args...) + _, err := fmt.Fprintf(b, format, args...) if err != nil { t.Fatalf("Writing to %s: %v", large, err) } @@ -240,6 +242,9 @@ func TestLargeDefs(t *testing.T) { printf("\"`\n") } printf("}\n") + if err = b.Flush(); err != nil { + t.Fatal(err) + } if err = f.Close(); err != nil { t.Fatal(err) }