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CPU-Load comparison WDM/VxD

OSR_Community_UserOSR_Community_User Member Posts: 110,217
Hi all,

today I have compared the CPU load of our old VxD with the
CPU load of our new WDM driver under Win98.

It looks like Win98 needs much more CPU resources to
communicate with an WDM driver rather than with our old VxD.

It is in both cases a "standard" driver that only uses an IOCTL
interface to communicate with an Win32 application.
Both drivers are as much identical as the appropriate
driver architecture allows.

I used Intel's VTune and the MS System Monitor to compare both
drivers:

WDM VxD
----------------------------------
total CPU: 31% 15%

VTune:
NTKERN 4,94% 0,70%
KERNEL32 4,66% 1,44%

my VxD/WDM: 0,14% 0,15%


As you can easily see, my driver consumes in both cases nearly
the same ammount of CPU power. But there are two components
(NTKERN, KERNEL32) that do need more CPU power when using the
WDM driver.
As far as I know, NTKERN is needed under Win98 to create
the IRP's (including the IOCTL's) to an WDM driver.

Does this so much influence the total CPU load?

Anybody else here with similar experiences?

Best Regards,
Carsten
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