What steps will reproduce the problem? 1. 使用CMSGC，系统运行一段时间后观察gclogviewer

What is the expected output? What do you see instead? Live Data Size Trend视图和Promotion To Old Size Trend视图均显示出大量负数值，详见附件图

What version of the product are you using? On what operating system? gclogviewer-0.3, jdk1.6.0_26

Please provide any additional information below.