numeric issues (#1982)

core/src/main/java/com/taobao/arthas/core/command/monitor200/MonitorAdviceListener.java

@@ -94,7 +94,7 @@ class MonitorAdviceListener extends AdviceListenerAdapter {
         if (timer == null) {
             timer = new Timer("Timer-for-arthas-monitor-" + process.session().getSessionId(), true);
             timer.scheduleAtFixedRate(new MonitorTimer(monitorData, process, command.getNumberOfLimit()),
-                    0, command.getCycle() * 1000);
+                    0, command.getCycle() * 1000L);
         }
     }
 

core/src/main/java/com/taobao/arthas/core/command/monitor200/ThreadSampler.java

@@ -118,7 +118,7 @@ public class ThreadSampler {
         // Compute cpu usage
         final HashMap<ThreadVO, Double> cpuUsages = new HashMap<ThreadVO, Double>(threads.size());
         for (ThreadVO thread : threads) {
-            double cpu = sampleIntervalNanos == 0 ? 0 : (deltas.get(thread) * 10000 / sampleIntervalNanos / 100.0);
+            double cpu = sampleIntervalNanos == 0 ? 0 : (Math.rint(deltas.get(thread) * 10000.0 / sampleIntervalNanos) / 100.0);
             cpuUsages.put(thread, cpu);
         }