Inside Windows 2000一书中的不明白之处

第三章system mechanisms  第一节Trap Dispatching
1、
在Predefined IRQLs 这部分说：
The system\'s real-time clock uses profile level when kernel profiling, a performance measurement mechanism, is enabled. When kernel profiling is active, the kernel\'s profiling trap handler records the address of the code that was executing when the interrupt occurred.
其中profile level 和 kernel profiling是什么意思？
2、
在Windows 2000 and Real-Time Processing这部分说：
Deadline requirements, either hard or soft, characterize real-time environments. Hard real-time systems have deadlines that the system must meet to avoid catastrophic failures such as loss of equipment or life. Soft real-time systems have deadlines that the system can miss, but timeliness is still a desirable trait.
其中Deadline指的是什么？

上一个是说内核性能分析
比如是找到哪段代码是调用最频繁的
哪段代码是花时间最长的

下一个说实时控制的延时的底限.......

多贴一点。我帮你看看。