Total CPU usage %

[Yasz]

Hi Guys,

Would you please help to figure out which API structure can provide the total CPU usage(as percentage %) for Windows 7 similar to the one shown the Task manager?

I found some example but tend to be complex calculations to calculate individual process then come up with the total.

Thanks
Yas

[kbw]

You need to use WMI.

You can start reading here and follow the links into MSDN WMI.
https://blogs.technet.com/b/heyscriptingguy/archive/2011/09/26/use-powershell-and-wmi-to-get-processor-information.aspx?Redirected=true

[modoran]

WMI is not required if you are not familiar to COM. This is an alternative solution:
http://www.codeproject.com/Articles/3413/How-to-get-CPU-usage-by-performance-counters-witho

[Computergeek01]

The "NtQuerySystemInformation()" function is undocumented? Someone should probably tell Microsoft then: http://msdn.microsoft.com/en-us/library/windows/desktop/ms724509(v=vs.85).aspx

[kbw]

Yes, it's "undocumented", despite a page being available for it.

The first thing on the page is:

[NtQuerySystemInformation may be altered or unavailable in future versions of Windows. Applications should use the alternate functions listed in this topic.]

[Computergeek01]

That to me says "unsupported" which is a little different. There are plenty of functions in the WinAPI that are truly undocumented. Here is a partial list of some of them: http://undocumented.ntinternals.net/

Maybe I'm just splitting hairs but unsupported means they plan on replacing the function eventually where as undocumented means you probably shouldn't use that function at all.

[kbw]

Maybe I'm just splitting hairs but ...

Yes, I think you're splitting hairs.

[modoran]

You can use GetSystemTimes() APi instead of NtQuerySystemInformation if you want to use only documented APIs. You will get the same information.
http://msdn.microsoft.com/en-us/library/windows/desktop/ms724400(v=vs.85).aspx

Example code:
http://www.codeproject.com/Articles/9113/Get-CPU-Usage-with-GetSystemTimes

[Yasz]

Thank you all,

I found this good example:
http://code.msdn.microsoft.com/windowsdesktop/Use-PerformanceCounter-to-272d57a1