Kees Vos (kees++at++demeern.sgi.com)
Thu, 12 Jan 1995 16:03:04 +0100
I am not sure if this is will help for your problem but you
can control the kernel input buffering on the serial port.
In your case it would probably be best to fully disable
buffering. This will result in some extra CPU overhead for the
serial port I/O but it will reduce the latencies.
To do this you must modify in the file:
/var/sysgen/master.d/sduart the followng line:
int duart_rsrv_duration = (HZ/50);
Change the value for this parameter from HZ/50 to 0
After this is done you have to build a new kernel and reboot.
Regards,
Kees!
[Quoting Riccardo Camiciottoli, on Jan 12, 12:04, in "Serial port ..."]
> Hi,
> I'm building a Virtual Reality environement with Performer on
> a SG Indy running IRIX 5.2 and I connected a VPL DataGlove
> to it via serial port. It works, but there is a little problem...
> Data sent by VPL glove are "chunked" by Indy and then
> by Performer at lower speed, therefore some of the VPL data are
> deliberately lost. Instead of losing these data, it seems that Indy
> store it in a buffer associated with the serial port and "chunk"
> them later. I would know if it's possible to avoid that storing,
> "chunking" always new data, that is, for example, reducing or
> eliminating this buffer. Please send the answer to email:
> camiciot++at++aguirre.ing.unifi.it
>
[End of quote from Riccardo Camiciottoli, on Jan 12, 12:04]
-- ______________________________________________________________________Kees Vos Email : kees++at++demeern.sgi.com MCA Super-Computing Team Voicemail: 5-9335 Silicon Graphics (The Netherlands) Phone : (31) 3406 21711 Fax : (31) 3406 21454 ______________________________________________________________________
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