Re: [Dev-C++] Calculating Time in milliseconds

[Per W. <pw...@ia...>]

As I said, the performance counters (which are extra registers inside
Pentium-class processors) can keep track of the individual clock cycles of
the processor, i.e. better than ns resolution.

/Per W

On Tue, 9 Nov 2004, Rob Lawless wrote:

> sorry but i would like relative time in ms resolution....
> i tried using the getTickCount() but this does not seem to be very accurate
> if i need an ms value <32 ms
> any other suggestions?
> also is nanosecond resolution possible?
> regards
> Rob
> ----- Original Message -----
> From: "Per Westermark" <pw...@ia...>
> To: "Rob Lawless" <rob...@nt...>
> Cc: "DEV-CPP" <dev...@li...>
> Sent: Monday, November 08, 2004 10:55 PM
> Subject: Re: [Dev-C++] Calculating Time in milliseconds
>
>
> > Do you want absolute time or relative time in ms resolution?
> >
> > For Win32, you can use GetTickCount() that gives number of ms since the
> > machine booted. It overflows every 49.7 days.
> >
> > However, it doesn't tick every ms. For a workstation I think it change
> > value every 32 ms.
> >
> > I haven't bothered to test, but I think the tick interval depends on the
> > length of time strata used by the windows installation for task switching,
> > i.e. it will vary between workstation and server installation.
> >
> > For better time intervals you can use the performance counters in windows
> > - they count time in clock cycles of the processor.
> >
> > On a unix machine you can use gettimeofday() to get absolute time down
> > to us resolution, but for this function too, the time is of course not
> > stepped every microsecond. Note that this function - as compared to the
> > Win32 GetTickCount() function - takes some time to call, so a program
> > making large amount of calls will get slowed down.
> >
> > /Per W
> >
> > On Mon, 8 Nov 2004, Rob Lawless wrote:
> >
> > > Hey folks just reading the <ctime> documentation which can only specify
> a mimimun time in seconds...does anyone know how to calulate a time interval
> in milliseconds?
> > > regards
> > > Rob
> >
>
>
>
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