CallNtPowerInformation() in windows7

NTDEV
1

hi all,
i found some issue while using the API CallNtPowerInformation(ProcessorInformation,) in windows 7.
in windows vista and windows xp it works fine and returns the same value of frequency.
There is the difference between the return paramters of the functions called in windows vista and windows 7. The max freq is showing same but there is difference between the current frequency. There is difference of almost 20-30 Mhz between two OS.
What could be the issue? is it related to some calculation differnce in HAL?
if doesn anybody have any info on this then reply me,
thanks
Hits

2

xxxxx@yahoo.co.in wrote:

i found some issue while using the API CallNtPowerInformation(ProcessorInformation,) in windows 7.
in windows vista and windows xp it works fine and returns the same value of frequency.
There is the difference between the return paramters of the functions called in windows vista and windows 7. The max freq is showing same but there is difference between the current frequency. There is difference of almost 20-30 Mhz between two OS.
What could be the issue? is it related to some calculation differnce in HAL?

Yep. There is no CPU register that contains the actual clock frequency,
so the HAL does the best it can to compute that clock frequency by
timing a hard looop. That’s an asynchronous process, so it is not 100%
precise.

How on earth could this possibly matter?

–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.

3

yes, but why it is same in case of windows xp and vista?
it is differnt only in windows 7.