智能Xplorer最佳策略是什么

我在ISE 14.7上运行SmartXplorer以优化时序性能。
结果显示，7种策略中有4种的时间分数为0.在这些情况下，最坏情况的松弛是：
0.112ns MapRuntime
0.108ns MapLogicOpt
0.108ns MapLogOptRegDup
0.270ns MapExtraEffort2
SmartXplorer说MapRunTime是最好的策略。
MapExtraEffort2不应该是最好的，因为它具有最高的最坏情况下的松弛？
谢谢，
约翰



以下为原文

I am running SmartXplorer on ISE 14.7 to optimize timing performance.  The results show that 4 of the 7 strategies have a timing score of 0.   In these cases, the worst-case slacks are:
0.112ns MapRunTime
0.108ns MapLogicOpt
0.108ns MapLogOptRegDup
0.270ns MapExtraEffort2  

SmartXplorer says that MapRunTime is the best strategy.  Shouldn't MapExtraEffort2 be the best since it has the highest worst-case slack?

thanks,
John