[ENet-discuss] timer resolution

[Lee Salzman]

Okay, I added this stuff in to my code base. Not sure when it will be
checked into CVS though because I have stuff I need to finish otherwise
(which may take quite a while).

Lee

On Sun, Feb 29, 2004 at 10:04:17AM +0000, Brad Monahan wrote:
> I decided to use timeGetTime() with timeBeginPeriod() / timeEndPeriod() 
> instead of the performance timers. I figured the nanosecond resolution 
> wasn't _needed_ and a lot more editing of the library would have to be 
> done. I also thought that anything <= 1ms resolution was good enough. I'm 
> much more satisfied with that than with 10-20ms resolution. To implement 
> you need to add two lines and edit two lines in the library as follows.
> 
> This needs to be added to enet_initialize():
> timeBeginPeriod(1);
> 
> This needs to be added to enet_deinitialize();
> timeEndPeriod(1);
> 
> This needs to be editing in enet_time_get():
> from
> return (enet_uint32) GetTickCount () - timeBase;
> to
> return (enet_uint32) timeGetTime () - timeBase;
> 
> This needs to be edited in enet_time_set():
> from
> timeBase = (enet_uint32) GetTickCount () - newTimeBase;
> to
> timeBase = (enet_uint32) timeGetTime () - newTimeBase;
> 
> 
> The timeBeginPeriod() and timeEndPeriod() functions lowers the granularity 
> of the timer to 1ms. timeEndPeriod() must be called with the same parameter 
> used in timeBeginTime().
> 
> 
> -Brad
> 
> 
> 
> 
> 
> >From: Lee Salzman <lsalzman at telerama.com>
> >Reply-To: Discussion of the ENet library <enet-discuss at cubik.org>
> >To: Discussion of the ENet library <enet-discuss at cubik.org>
> >Subject: Re: [ENet-discuss] timer resolution
> >Date: Sat, 28 Feb 2004 17:48:23 -0500
> >
> >I bid thee: send me a patch. :) I don't know quite enough about Win32 to
> >implement this myself, but just enough to get myself in trouble. If the
> >patch looks sane, I will integrate it.
> >
> >In so far as unix playforms and portability, I have to count on
> >gettimeofday() to do the Right Thing with respect to timer resolution. I
> >know Linux is really good about this and does not exclusively rely on
> >its 100 Hz timer, and augments it with info from the time stamp counter
> >on x86.
> >
> >Lee
> >
> >On Sat, Feb 28, 2004 at 09:31:24PM +0000, Brad Monahan wrote:
> >> I noticed enet uses GetTickCount() for timing in the win32 side of 
> >things.
> >> I'm in the process of changing this so it uses QueryPerformanceCounter
> >> instead, falling back on timeGetTime and timeBeginPeriod/timeEndPeriod 
> >(for
> >> up to 1ms resolution) if the performance timer is not available. I'm 
> >using
> >> the roundTripTime calculated by enet for the interpolation/extrapolation 
> >on
> >> my client and it seems to not be accurate enough for this purpose. 
> >Should I
> >> even be doing this? I thought that was a feature of enet. It keeps track 
> >of
> >> the average ping so you can do stuff like that. I know GetTickCount() 
> >has
> >> _atleast_ a 10ms resolution if not closer to 20ms (if I remember 
> >correctly)
> >> and the performance timer has well under 1ms resolution. This is just a
> >> suggestion post for the next version of enet. It would be very easy to
> >> implement and there would be a much greater performance aspect. I don't
> >> know how good the unix timer is or it's resolution, so I can't offer
> >> anything on the unix side of things, but this would make a great 
> >addition
> >> on the win32 side.
> >>
> >> -Brad
> >>
> >
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