ISR和DPC

ISR：Interrupt Service Routines （中断服务例程

必须马上做的事情，比如硬件中断，响应鼠标点击

DPC：Deferred Procedure Call Details（延迟过程调用

可以推迟做的事情，比如大数据拷贝，U盘拷贝电影。

APC: Asynchronous Procedure Calls(异步过程调用

An asynchronous procedure call (APC) is a function that executes asynchronously in the context of a particular thread. When an APC is queued to a thread, the system issues a software interrupt. The next time the thread is scheduled, it will run the APC function. An APC generated by the system is called a kernel-mode APC. An APC generated by an application is called a user-mode APC. A thread must be in an alertable state to run a user-mode APC.

Windows中断请求级别

IRQL	Interrupts Masked Off	Driver Routines
PASSIVE_LEVEL	None	PASSIVE_LEVEL
APC_LEVEL	APC_LEVEL interrupts	APC_LEVEL
DISPATCH_LEVEL	DISPATCH_LEVEL ，APC_LEVEL interrupts	DISPATCH_LEVEL
DIRQL	All interrupts at IRQL<= DIRQL	DIRQL

参考

Managing Hardware Priorities

IRQL

Deferred Procedure Call Details（延迟过程调用详解）

Asynchronous Procedure Calls