From: Russ Cox <rsc@golang.org>
Date: Thu, 19 Jul 2018 17:23:32 +0000 (-0400)
Subject: cmd/go/internal/par: actually make par.Work run things in parallel
X-Git-Tag: go1.11beta2~13
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=dada467fc688ef5970bf4af30c2644c0d2ccdb54;p=gostls13.git

cmd/go/internal/par: actually make par.Work run things in parallel

This was an unfortunate debugging print introduced
while working on the unfortunately large CL 123576.
At least now we're done with that awfulness.

Change-Id: Ib83db59382a799f649832d22d3c6f039d2ef9d2c
Reviewed-on: https://go-review.googlesource.com/125015
Reviewed-by: Bryan C. Mills <bcmills@google.com>
---

diff --git a/src/cmd/go/internal/par/work.go b/src/cmd/go/internal/par/work.go
index 6543f1a35c..a568c86f60 100644
--- a/src/cmd/go/internal/par/work.go
+++ b/src/cmd/go/internal/par/work.go
@@ -55,7 +55,6 @@ func (w *Work) Do(n int, f func(item interface{})) {
 	if n < 1 {
 		panic("par.Work.Do: n < 1")
 	}
-	n = 1
 	if w.running >= 1 {
 		panic("par.Work.Do: already called Do")
 	}
diff --git a/src/cmd/go/internal/par/work_test.go b/src/cmd/go/internal/par/work_test.go
index 71c0395d3b..53a715ea81 100644
--- a/src/cmd/go/internal/par/work_test.go
+++ b/src/cmd/go/internal/par/work_test.go
@@ -7,6 +7,7 @@ package par
 import (
 	"sync/atomic"
 	"testing"
+	"time"
 )
 
 func TestWork(t *testing.T) {
@@ -30,6 +31,30 @@ func TestWork(t *testing.T) {
 	}
 }
 
+func TestWorkParallel(t *testing.T) {
+	var w Work
+
+	for tries := 0; tries < 10; tries++ {
+		const N = 100
+		for i := 0; i < N; i++ {
+			w.Add(i)
+		}
+		start := time.Now()
+		var n int32
+		w.Do(N, func(x interface{}) {
+			time.Sleep(1 * time.Millisecond)
+			atomic.AddInt32(&n, +1)
+		})
+		if n != N {
+			t.Fatalf("par.Work.Do did not do all the work")
+		}
+		if time.Since(start) < N/2*time.Millisecond {
+			return
+		}
+	}
+	t.Fatalf("par.Work.Do does not seem to be parallel")
+}
+
 func TestCache(t *testing.T) {
 	var cache Cache