[lug] 16550 Serial port buffering?

[D. Stimits]

"Scott A. Herod" wrote:
> 
> After 3 days of trying to get it to work....
> 
>   "man setserial"  search for low_latency.

Makes me wonder if this could have a beneficial effect on the serial
port of a 56k modem while working with games that require low latency.
When I get around to it, I think I'll give it a try (not exactly serious
work, but hey, someone needs to be less serious).

D. Stimits, stimits at idcomm.com

> 
> Apparently it was the serial port driver, not context switching
> in the kernel.
> 
> Scott
> 
> "Scott A. Herod" wrote:
> >
> > Hello,
> >
> >   We're having a hard time getting rapid response from a clock attached
> > to the 16550 serial port on my machine.  This is RH 7.1 with the
> > 2.4.2 kernal.  We believe that we're seeing a big delay ( on the order
> > of 10 msecs ) between the time the clock sends a byte and the
> > time that select in a user-land process returns with that byte.
> >
> >   A couple of questions:
> >
> >   Is this an indication of context switching and if so is it possible
> > to speed it up?
> >
> >   Is there a way to trigger another line on the serial port when the
> > read occurs so that I can watch a scope to verify that I am getting
> > this delay?
> >
> >   Any other thoughts would be greatly appreciated.
> >
> > Thanks,
> >
> > Scott
> > _______________________________________________
> > Web Page:  http://lug.boulder.co.us
> > Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
> _______________________________________________
> Web Page:  http://lug.boulder.co.us
> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug