device: add benchmark for UAPI Device.IpcGetOperation

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

device/device_test.go

@@ -10,6 +10,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net"
 	"sync"
 	"sync/atomic"
@@ -340,3 +341,14 @@ func BenchmarkThroughput(b *testing.B) {
 	b.ReportMetric(float64(elapsed)/float64(b.N), "ns/op")
 	b.ReportMetric(1-float64(b.N)/float64(sent), "packet-loss")
 }
+
+func BenchmarkUAPIGet(b *testing.B) {
+	pair := genTestPair(b)
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		pair[0].dev.IpcGetOperation(ioutil.Discard)
+	}
+}