讨论 IO－NO―increment

在iocompleterequest  里的  io_no_increment
是用来提高用户等待线程的优先级

如果你的IRP处理例程耗时比较多，就有必要设置一些常数，
可以参考wdm.h，不过一般没有必要。

IO_NO_INCREMENT 表明不提升

相关值如下
// Priority increment when no I/O has been done.  This is used by device
// and file system drivers when completing an IRP (IoCompleteRequest).
//

#define IO_NO_INCREMENT                 0


//
// Priority increment for completing CD-ROM I/O.  This is used by CD-ROM device
// and file system drivers when completing an IRP (IoCompleteRequest)
//

#define IO_CD_ROM_INCREMENT             1

//
// Priority increment for completing disk I/O.  This is used by disk device
// and file system drivers when completing an IRP (IoCompleteRequest)
//

#define IO_DISK_INCREMENT               1



//
// Priority increment for completing keyboard I/O.  This is used by keyboard
// device drivers when completing an IRP (IoCompleteRequest)
//

#define IO_KEYBOARD_INCREMENT           6


//
// Priority increment for completing mailslot I/O.  This is used by the mail-
// slot file system driver when completing an IRP (IoCompleteRequest).
//

#define IO_MAILSLOT_INCREMENT           2


//
// Priority increment for completing mouse I/O.  This is used by mouse device
// drivers when completing an IRP (IoCompleteRequest)
//

#define IO_MOUSE_INCREMENT              6


//
// Priority increment for completing named pipe I/O.  This is used by the
// named pipe file system driver when completing an IRP (IoCompleteRequest).
//

#define IO_NAMED_PIPE_INCREMENT         2

//
// Priority increment for completing network I/O.  This is used by network
// device and network file system drivers when completing an IRP
// (IoCompleteRequest).
//

#define IO_NETWORK_INCREMENT            2


//
// Priority increment for completing parallel I/O.  This is used by parallel
// device drivers when completing an IRP (IoCompleteRequest)
//

#define IO_PARALLEL_INCREMENT           1

//
// Priority increment for completing serial I/O.  This is used by serial device
// drivers when completing an IRP (IoCompleteRequest)
//

#define IO_SERIAL_INCREMENT             2

//
// Priority increment for completing sound I/O.  This is used by sound device
// drivers when completing an IRP (IoCompleteRequest)
//

#define IO_SOUND_INCREMENT              8

//
// Priority increment for completing video I/O.  This is used by video device
// drivers when completing an IRP (IoCompleteRequest)
//

#define IO_VIDEO_INCREMENT              1

如果你的驱动可以很快完成I/O请求，用IO_NO_INCREMENT
如果你的驱动不能很快完成I/O请求，则用户线程可能已经等待很久，这时就需要适当给它一点奖励，“你辛苦了，排了这么长时间，让你先来”

这些值是设备相关的。

关注

哦  原来是这样的