如果在网上搜索一下，反映Windows7系统下玩网游时网络延时比较高的人实在太多了，也就是Ping比平时在XP系统的时候要高一点，一直找不到原因，很苦恼。今天我们终于找到理由了，原来是Windows7的一个服务在作怪，这个服务叫：Multimedia Class Scheduler。
Multimedia Class Scheduler 这个服务在微软的官方解释是：
The Multimedia Class Scheduler service (MMCSS) enables multimedia applications to ensure that their time-sensitive processing receives prioritized access to CPU resources. This service enables multimedia applications to utilize as much of the CPU as possible without denying CPU resources to lower-priority applications.
MMCSS uses information stored in the registry to identify supported tasks and determine the relative priority of threads performing these tasks. Each thread that is performing work related to a particular task calls the AvSetMmMaxThreadCharacteristics or AvSetMmThreadCharacteristics function to inform MMCSS that it is working on that task.
For an example of a program that uses MMCSS, see Exclusive-Mode Streams
