Use atomic operations for threshold protection

atomic.StoreUint32 and atomic.LoadUint32 are used for accessing
threshold level in Logger.
They are much faster than mutexes.

Change-Id: Idd4db0ab2df1e5d783abc13c0b29c7560a1e0734
Signed-off-by: Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>

2 files changed, 5 insertions, 12 deletions

diff --git a/logger/logger.go b/logger/logger.go
index 7a2775c..c31bb1b 100644
--- a/logger/logger.go
+++ b/logger/logger.go
@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"os"
 	"sync"
+	"sync/atomic"
 )
 
 const (
@@ -59,24 +60,18 @@ func (l *Logger) SetThreshold(level Level) error {
 		return ErrInvalidLogLevel
 	}
 
-	l.mutex.Lock()
-	defer l.mutex.Unlock()
-	l.threshold = level
+	atomic.StoreUint32((*uint32)(&l.threshold), uint32(level))
 	return nil
 }
 
 // Threshold returns current Logger's filter level.
 func (l *Logger) Threshold() Level {
-	l.mutex.Lock()
-	defer l.mutex.Unlock()
-	return l.threshold
+	return Level(atomic.LoadUint32((*uint32)(&l.threshold)))
 }
 
 // PassThreshold verifies if message with given level passes threshold and should be logged.
 func (l *Logger) PassThreshold(level Level) bool {
-	l.mutex.Lock()
-	defer l.mutex.Unlock()
-	return (level <= l.threshold)
+	return (level <= l.Threshold())
 }
 
 // AddBackend adds or replaces a backend with given name.
diff --git a/logger/logger_test.go b/logger/logger_test.go
index b3554f3..85efc65 100644
--- a/logger/logger_test.go
+++ b/logger/logger_test.go
@@ -93,9 +93,9 @@ var _ = Describe("Logger", func() {
 		It("should create a new default logger object", func() {
 			Expect(L).NotTo(BeNil())
 			Expect(L.mutex).NotTo(BeNil())
+			Expect(L.threshold).To(Equal(DefaultThreshold))
 			L.mutex.Lock()
 			defer L.mutex.Unlock()
-			Expect(L.threshold).To(Equal(DefaultThreshold))
 			Expect(L.backends).To(BeEmpty())
 		})
 	})
@@ -105,8 +105,6 @@ var _ = Describe("Logger", func() {
 				func(level Level) {
 					err := L.SetThreshold(level)
 					Expect(err).NotTo(HaveOccurred())
-					L.mutex.Lock()
-					defer L.mutex.Unlock()
 					Expect(L.threshold).To(Equal(level))
 				},
 				T.Entry("EmergLevel", EmergLevel),