Make the cpu usage percent always greater than 1 (#5422)

* fix bug #5417, make the CPU usage percent always >= 1

oap-server/analyzer/agent-analyzer/src/main/java/org/apache/skywalking/oap/server/analyzer/provider/jvm/JVMSourceDispatcher.java

@@ -77,7 +77,9 @@ public class JVMSourceDispatcher {
         serviceInstanceJVMCPU.setName(serviceInstance);
         serviceInstanceJVMCPU.setServiceId(serviceId);
         serviceInstanceJVMCPU.setServiceName(service);
-        serviceInstanceJVMCPU.setUsePercent(cpu.getUsagePercent());
+        // If the cpu usage percent is less than 1, will set to 1
+        double adjustedCpuUsagePercent = Math.max(cpu.getUsagePercent(), 1.0);
+        serviceInstanceJVMCPU.setUsePercent(adjustedCpuUsagePercent);
         serviceInstanceJVMCPU.setTimeBucket(timeBucket);
         sourceReceiver.receive(serviceInstanceJVMCPU);
     }

oap-server/server-fetcher-plugin/kafka-fetcher-plugin/src/test/java/org/apache/skywalking/oap/server/analyzer/agent/kafka/provider/handler/JVMMetricsHandlerTest.java

@@ -46,6 +46,8 @@ import org.junit.Before;
 import org.junit.ClassRule;
 import org.junit.Test;
 
+import static org.hamcrest.CoreMatchers.is;
+
 public class JVMMetricsHandlerTest {
     private static final String TOPIC_NAME = "skywalking-metrics";
     private JVMMetricsHandler handler = null;
@@ -59,6 +61,8 @@ public class JVMMetricsHandlerTest {
         @Override
         protected void verify(final List<Source> sourceList) throws Throwable {
             Assert.assertTrue(sourceList.get(0) instanceof ServiceInstanceJVMCPU);
+            ServiceInstanceJVMCPU serviceInstanceJVMCPU = (ServiceInstanceJVMCPU) sourceList.get(0);
+            Assert.assertThat(serviceInstanceJVMCPU.getUsePercent(), is(1.0));
             Assert.assertTrue(sourceList.get(1) instanceof ServiceInstanceJVMMemory);
             Assert.assertTrue(sourceList.get(2) instanceof ServiceInstanceJVMMemoryPool);
             Assert.assertTrue(sourceList.get(3) instanceof ServiceInstanceJVMGC);