File size: 1,180 Bytes
f7a7bb1 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | // Copyright 2024 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.
package atomic_test
import (
"internal/runtime/atomic"
"testing"
)
func TestXchg8(t *testing.T) {
var a [16]uint8
for i := range a {
next := uint8(i + 50)
a[i] = next
}
b := a
// Compare behavior against non-atomic implementation. Expect the operation
// to work at any byte offset and to not clobber neighboring values.
for i := range a {
next := uint8(i + 100)
pa := atomic.Xchg8(&a[i], next)
pb := b[i]
b[i] = next
if pa != pb {
t.Errorf("atomic.Xchg8(a[%d]); %d != %d", i, pa, pb)
}
if a != b {
t.Errorf("after atomic.Xchg8(a[%d]); %d != %d", i, a, b)
}
if t.Failed() {
break
}
}
}
func BenchmarkXchg8(b *testing.B) {
var x [512]uint8 // give byte its own cache line
sink = &x
for i := 0; i < b.N; i++ {
atomic.Xchg8(&x[255], uint8(i))
}
}
func BenchmarkXchg8Parallel(b *testing.B) {
var x [512]uint8 // give byte its own cache line
sink = &x
b.RunParallel(func(pb *testing.PB) {
i := uint8(0)
for pb.Next() {
atomic.Xchg8(&x[255], i)
i++
}
})
}
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