runtime: preempt goroutines for GC
The last patch for preemptive scheduler,
with this change stoptheworld issues preemption
requests every 100us.
Update #543.
R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/10264044
diff --git a/src/pkg/runtime/proc_test.go b/src/pkg/runtime/proc_test.go
index 83368e0..605f747 100644
--- a/src/pkg/runtime/proc_test.go
+++ b/src/pkg/runtime/proc_test.go
@@ -157,6 +157,36 @@
<-done
}
+// The function is used to test preemption at split stack checks.
+// Declaring a var avoids inlining at the call site.
+var preempt = func() int {
+ var a [128]int
+ sum := 0
+ for _, v := range a {
+ sum += v
+ }
+ return sum
+}
+
+func TestPreemptionGC(t *testing.T) {
+ // Test that pending GC preempts running goroutines.
+ const P = 5
+ defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(P + 1))
+ var stop uint32
+ for i := 0; i < P; i++ {
+ go func() {
+ for atomic.LoadUint32(&stop) == 0 {
+ preempt()
+ }
+ }()
+ }
+ for i := 0; i < 10; i++ {
+ runtime.Gosched()
+ runtime.GC()
+ }
+ atomic.StoreUint32(&stop, 1)
+}
+
func stackGrowthRecursive(i int) {
var pad [128]uint64
if i != 0 && pad[0] == 0 {
