remove three other roundings in cpu calculation

heron/packing/src/java/com/twitter/heron/packing/builder/Container.java

@@ -151,8 +151,8 @@ private void assertHasSpace(Resource resource) throws ResourceExceededException
     Resource usedResources = this.getTotalUsedResources();
     ByteAmount newRam =
         usedResources.getRam().plus(resource.getRam()).increaseBy(paddingPercentage);
-    double newCpu = Math.round(
-        PackingUtils.increaseBy(usedResources.getCpu() + resource.getCpu(), paddingPercentage));
+    double newCpu =
+        PackingUtils.increaseBy(usedResources.getCpu() + resource.getCpu(), paddingPercentage);
     ByteAmount newDisk =
         usedResources.getDisk().plus(resource.getDisk()).increaseBy(paddingPercentage);
 

heron/packing/src/java/com/twitter/heron/packing/builder/PackingPlanBuilder.java

@@ -352,12 +352,12 @@ private static Set<PackingPlan.ContainerPlan> buildContainerPlans(
             new Resource(instanceCpu, instanceRam, instanceDisk)));
       }
 
-      containerCpu += (paddingPercentage * containerCpu) / 100;
+      containerCpu = PackingUtils.increaseBy(containerCpu, paddingPercentage);
       containerRam = containerRam.increaseBy(paddingPercentage);
       containerDiskInBytes = containerDiskInBytes.increaseBy(paddingPercentage);
 
       Resource resource =
-          new Resource(Math.round(containerCpu), containerRam, containerDiskInBytes);
+          new Resource(containerCpu, containerRam, containerDiskInBytes);
 
       PackingPlan.ContainerPlan containerPlan =
           new PackingPlan.ContainerPlan(containerId, instancePlans, resource);

heron/packing/src/java/com/twitter/heron/packing/utils/PackingUtils.java

@@ -58,8 +58,8 @@ private static void assertIsValidInstance(Resource instanceResources,
           instanceRam, maxContainerResources.getRam()));
     }
 
-    double instanceCpu = Math.round(PackingUtils.increaseBy(
-        instanceResources.getCpu(), paddingPercentage));
+    double instanceCpu = PackingUtils.increaseBy(
+        instanceResources.getCpu(), paddingPercentage);
     if (instanceCpu > maxContainerResources.getCpu()) {
       throw new PackingException(String.format(
           "This instance requires containers with at least %s cpu cores. The current max container"