Go counter benchmarks

gistfile1.txt

/* result */
$ go test -test.bench=. -test.cpu=1,2,4,8 -test.benchtime=10s .
goos: linux
goarch: amd64
BenchmarkAdd            1000000000               6.97 ns/op
BenchmarkAdd-2          532704848               21.1 ns/op
BenchmarkAdd-4          675975466               17.8 ns/op
BenchmarkAdd-8          767997027               15.7 ns/op
BenchmarkCASPause       1000000000               8.92 ns/op
BenchmarkCASPause-2     1000000000               8.92 ns/op
BenchmarkCASPause-4     1000000000               8.92 ns/op
BenchmarkCASPause-8     1000000000               9.21 ns/op
BenchmarkCAS            1000000000               8.92 ns/op
BenchmarkCAS-2          237693028               50.6 ns/op
BenchmarkCAS-4          185520495               64.7 ns/op
BenchmarkCAS-8          100000000              104 ns/op
PASS

/* con.s */
// +build amd64

TEXT ·procyield(SB), $0
    JMP runtime·procyield(SB)

/* con_test.go */

package con

import (
        "sync/atomic"
        "testing"
)

func BenchmarkAdd(b *testing.B) {
        c := uint64(0)
        b.RunParallel(func(pb *testing.PB) {
                for pb.Next() {
                        atomic.AddUint64(&c, 42)
                }
        })
}

func procyield()

func BenchmarkCASPause(b *testing.B) {
        c := uint64(0)
        b.RunParallel(func(pb *testing.PB) {
                for pb.Next() {
                        cp := c + 42
                        stop := atomic.CompareAndSwapUint64(&c, c, cp)
                        for !stop {
                                procyield()
                                cp = c + 42
                                stop = atomic.CompareAndSwapUint64(&c, c, cp)
                        }
                }
        })
}
func BenchmarkCAS(b *testing.B) {
        c := uint64(0)
        b.RunParallel(func(pb *testing.PB) {
                for pb.Next() {
                        for stop := false; !stop; {
                                cp := c + 42
                                stop = atomic.CompareAndSwapUint64(&c, c, cp)
                        }
                }
        })
}