Timer resolution

Phil Torre ptorre at zetron.com
Fri Feb 21 23:15:29 UTC 2003


FWIW, we've done 10Mbit with a powerpc860 using a 64Hz tick rate.
I've never really stress-tested it, but it does ftp and telnet
and serves static web pages just fine.

-Phil

On Fri, Feb 21, 2003 at 07:44:32AM -0600, Joel Sherrill wrote:
> 
> 
> Nigel Spon wrote:
> > 
> > Hi,
> > 
> > If I might intrude for a moment with a simple user question; does
> > anyone know where or how I might discover the timer tick interval
> > limits for using the RTEMS network stack: i.e how often should
> > rtems_clock_tick() be called? I ask because it must have a bearing on
> > how well the TCP retransmit timers, etc will work, and I suspect there
> > is a minimum resolution requirement for 10Mbit and 100Mbit Ethernet...
> 
> The tftp and ttcp demos use 10,000 microseconds as their value.  Given
> that the source code is from FreeBSD, I would suspect that it doesn't 
> require a clock tick lower than that.  UNIX was never known for having
> low clock tick quantums.
> 
> My guess would be that anything 10 milliseconds or less would be fine.
> But I would love to hear from someone else.
> 
> > Thanks for any assistance,
> > 
> > Nigel
> > 
> > ---
> > "The Galaxy's a fun place. You'll need to have this fish in your ear."
> 
> -- 
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel at OARcorp.com                 On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> Support Available                (256) 722-9985



  




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