diff --git a/api/init.go b/api/init.go
index 27229201..d74e19a7 100644
--- a/api/init.go
+++ b/api/init.go
@@ -25,6 +25,7 @@ import (
 	metric_exporter "github.com/alibaba/sentinel-golang/exporter/metric"
 	"github.com/alibaba/sentinel-golang/util"
 	"github.com/pkg/errors"
+	_ "go.uber.org/automaxprocs"
 )
 
 // Initialization func initialize the Sentinel's runtime environment, including:
diff --git a/core/system_metric/sys_metric_stat.go b/core/system_metric/sys_metric_stat.go
index c8751419..d6e29f0e 100644
--- a/core/system_metric/sys_metric_stat.go
+++ b/core/system_metric/sys_metric_stat.go
@@ -176,6 +176,8 @@ func retrieveAndUpdateCpuStat() {
 		return
 	}
 
+	cpuPercent = cpuPercent / 100.0
+
 	cpuRatioGauge.Set(cpuPercent)
 
 	currentCpuUsage.Store(cpuPercent)
diff --git a/core/system_metric/sys_metric_stat_test.go b/core/system_metric/sys_metric_stat_test.go
index e3a6cdf3..86fba3f7 100644
--- a/core/system_metric/sys_metric_stat_test.go
+++ b/core/system_metric/sys_metric_stat_test.go
@@ -47,20 +47,8 @@ func TestCurrentCpuUsage(t *testing.T) {
 	assert.True(t, util.Float64Equals(v, cpuUsage))
 }
 
-func Test_getProcessCpuStat(t *testing.T) {
-	wg := &sync.WaitGroup{}
-	wg.Add(1)
-	go func() {
-		i := 0
-		wg.Done()
-		for i < 10000000000 {
-			i++
-			if i == 1000000000 {
-				i = 0
-			}
-		}
-	}()
-	wg.Wait()
+func TestGetProcessCpuStat(t *testing.T) {
+	upraiseCpuRate()
 
 	got, err := getProcessCpuStat()
 	if err != nil {
@@ -83,3 +71,28 @@ func Test_getProcessCpuStat(t *testing.T) {
 	assert.True(t, int(got) > 0)
 	time.Sleep(time.Millisecond * 200)
 }
+
+func TestRetrieveAndUpdateCpuStatReturnValueRange(t *testing.T) {
+	// Initial cpu retrieval.
+	retrieveAndUpdateCpuStat()
+	upraiseCpuRate()
+	time.Sleep(time.Millisecond * 200)
+	retrieveAndUpdateCpuStat()
+	assert.True(t, true, CurrentCpuUsage() < 1.0)
+}
+
+func upraiseCpuRate() {
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		i := 0
+		wg.Done()
+		for i < 10000000000 {
+			i++
+			if i == 1000000000 {
+				i = 0
+			}
+		}
+	}()
+	wg.Wait()
+}
diff --git a/go.mod b/go.mod
index f67c45a7..94b18ded 100644
--- a/go.mod
+++ b/go.mod
@@ -8,7 +8,8 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.9.0
 	github.com/shirou/gopsutil/v3 v3.21.6
-	github.com/stretchr/testify v1.6.1
+	github.com/stretchr/testify v1.7.1
+	go.uber.org/automaxprocs v1.5.3
 	go.uber.org/multierr v1.5.0
 	gopkg.in/yaml.v2 v2.3.0
 )
diff --git a/go.sum b/go.sum
index 53aa5abb..1a922233 100644
--- a/go.sum
+++ b/go.sum
@@ -213,6 +213,8 @@ github.com/pkg/profile v1.2.1/go.mod h1:hJw3o1OdXxsrSjjVksARp5W95eeEaEfptyVZyv6J
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/posener/complete v1.1.1/go.mod h1:em0nMJCgc9GFtwrmVmEMR/ZL6WyhyjMBndrE9hABlRI=
+github.com/prashantv/gostub v1.1.0 h1:BTyx3RfQjRHnUWaGF9oQos79AlQ5k8WNktv7VGvVH4g=
+github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
 github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
 github.com/prometheus/client_golang v0.9.3-0.20190127221311-3c4408c8b829/go.mod h1:p2iRAGwDERtqlqzRXnrOVns+ignqQo//hLXqYxZYVNs=
 github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=
@@ -268,8 +270,10 @@ github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.1 h1:5TQK59W5E3v0r2duFAb7P95B6hEeOyEnHRa8MjYSMTY=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/tklauser/go-sysconf v0.3.6 h1:oc1sJWvKkmvIxhDHeKWvZS4f6AW+YcoguSfRF2/Hmo4=
 github.com/tklauser/go-sysconf v0.3.6/go.mod h1:MkWzOF4RMCshBAMXuhXJs64Rte09mITnppBXY/rYEFI=
 github.com/tklauser/numcpus v0.2.2 h1:oyhllyrScuYI6g+h/zUvNXNp1wy7x8qQy3t/piefldA=
@@ -287,6 +291,8 @@ go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
 go.uber.org/atomic v1.6.0 h1:Ezj3JGmsOnG1MoRWQkPBsKLe9DwWD9QeXzTRzzldNVk=
 go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
+go.uber.org/automaxprocs v1.5.3 h1:kWazyxZUrS3Gs4qUpbwo5kEIMGe/DAvi5Z4tl2NW4j8=
+go.uber.org/automaxprocs v1.5.3/go.mod h1:eRbA25aqJrxAbsLO0xy5jVwPt7FQnRgjW+efnwa1WM0=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.3.0/go.mod h1:VgVr7evmIr6uPjLBxg28wmKNXyqE9akIJ5XnfpiKl+4=
 go.uber.org/multierr v1.5.0 h1:KCa4XfM8CWFCpxXRGok+Q0SS/0XBhMDbHHGABQLvD2A=
@@ -424,8 +430,9 @@ gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=