[PATCH] CPU-time clocks

[Yaakov (Cygwin/X)]

On Tue, 2011-05-17 at 07:58 +0200, Corinna Vinschen wrote:
> Thank you.  You can apply it, but while I was looking into it,
> this occured to me:
> 
> This conversion arithmetic from FILETIME to long long happens a lot
> in times.cc, even though it's absolutely not necessary.
> 
> The FILETIME struct is actually a LARGE_INTEGER in which just the
> QuadPart member is missing, unfortunately.  What we can do is to
> replace the bit shifting stuff with a simple cast:
> 
>   x = ((PLARGE_INTEGER) &kernel_time)->QuadPart
>       + ((PLARGE_INTEGER) &user_time)->QuadPart;

The MSDN docs on FILETIME[1] state:

> Do not cast a pointer to a FILETIME structure to either a ULARGE_INTEGER*
> or __int64* value because it can cause alignment faults on 64-bit Windows.

As I am by no means an expert on Win32 programming, I take that at face
value.

> Alternatively we can define kernel_time etc as LARGE_INTEGER and cast in
> the call to GetProcessTimes or just call NtQueryInformationProcess.

I have chosen the latter.  Revised patch attached.


Yaakov


[1] http://msdn.microsoft.com/en-us/library/ms724284(VS.85).aspx

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