runtime: add BenchmarkStackCopyWithStkobj

For benchmarking and improving recent stkobj-related changes.

Co-Authored-By: Cherry Mui <[email protected]>
Change-Id: I34c8b1a09e4cf98547460882b0d3908158269f57
Reviewed-on: https://go-review.googlesource.com/c/go/+/354071
Trust: Josh Bleecher Snyder <[email protected]>
Run-TryBot: Josh Bleecher Snyder <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>

src/runtime/stack_test.go

@@ -585,6 +585,34 @@ func count21(n int) int { return 1 + count22(n-1) }
 func count22(n int) int { return 1 + count23(n-1) }
 func count23(n int) int { return 1 + count1(n-1) }
 
+type stkobjT struct {
+ p *stkobjT
+ x int64
+ y [20]int // consume some stack
+}
+
+// Sum creates a linked list of stkobjTs.
+func Sum(n int64, p *stkobjT) {
+ if n == 0 {
+ return
+ }
+ s := stkobjT{p: p, x: n}
+ Sum(n-1, &s)
+ p.x += s.x
+}
+
+func BenchmarkStackCopyWithStkobj(b *testing.B) {
+ c := make(chan bool)
+ for i := 0; i < b.N; i++ {
+ go func() {
+ var s stkobjT
+ Sum(100000, &s)
+ c <- true
+ }()
+ <-c
+ }
+}
+
 type structWithMethod struct{}
 
 func (s structWithMethod) caller() string {