diff options
Diffstat (limited to 'libgo/go/runtime/testdata/testprog/gc.go')
| -rw-r--r-- | libgo/go/runtime/testdata/testprog/gc.go | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/libgo/go/runtime/testdata/testprog/gc.go b/libgo/go/runtime/testdata/testprog/gc.go index 9bb367c..a0c1f82 100644 --- a/libgo/go/runtime/testdata/testprog/gc.go +++ b/libgo/go/runtime/testdata/testprog/gc.go @@ -1,4 +1,4 @@ -// Copyright 2015 The Go Authors. All rights reserved. +// Copyright 2015 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. @@ -8,11 +8,14 @@ import ( "fmt" "os" "runtime" + "runtime/debug" + "sync/atomic" "time" ) func init() { register("GCFairness", GCFairness) + register("GCFairness2", GCFairness2) register("GCSys", GCSys) } @@ -72,3 +75,35 @@ func GCFairness() { time.Sleep(10 * time.Millisecond) fmt.Println("OK") } + +func GCFairness2() { + // Make sure user code can't exploit the GC's high priority + // scheduling to make scheduling of user code unfair. See + // issue #15706. + runtime.GOMAXPROCS(1) + debug.SetGCPercent(1) + var count [3]int64 + var sink [3]interface{} + for i := range count { + go func(i int) { + for { + sink[i] = make([]byte, 1024) + atomic.AddInt64(&count[i], 1) + } + }(i) + } + // Note: If the unfairness is really bad, it may not even get + // past the sleep. + // + // If the scheduling rules change, this may not be enough time + // to let all goroutines run, but for now we cycle through + // them rapidly. + time.Sleep(30 * time.Millisecond) + for i := range count { + if atomic.LoadInt64(&count[i]) == 0 { + fmt.Printf("goroutine %d did not run\n", i) + return + } + } + fmt.Println("OK") +} |