problems with CPU usage of serial ports

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2 total messages Started by Ulrich Grepel Tue, 03 Nov 1992 09:55

#95

Author: Ulrich Grepel
Date: Tue, 03 Nov 1992 09:55

20 lines
1465 bytes

Hi all,

I think I found another almost-bug:

Why is an unused serial port that is enabled in the /etc/ttys table
(with 19200 baud, hardware flow control, 8N1) using up most of the cpu?
The processes that are initiated by init on these ports use 15 to 30 
percent if you look with 'px xua', but you can get a little bit more
of the feeling if you try to (la)tex a large document or if you try
to compile something out of the project builder. You get the feeling
of an ol' 68030... (or even '20)

Might it be the case that empty ports generate interrupts that have
to be handled by the cpu? (I use a monostation of the first station
hardware design, hence no timed power on or new memory management.)

Any idea or comment is welcome, but please email me (no NeXTmail yet), 
since unfortunately I have not the time to read everything on this group.

Uli

Re: problems with CPU usage of serial ports

#1208

Author: Thomas Funke
Date: Wed, 04 Nov 1992 18:26

20 lines
1335 bytes

In article <1992Nov3.095549.29491@news.th-darmstadt.de>  
uli@aida.intellektik.informatik.th-darmstadt.de (Ulrich Grepel) writes:
> Hi all,
> 
> I think I found another almost-bug:
> 
> Why is an unused serial port that is enabled in the /etc/ttys table
> (with 19200 baud, hardware flow control, 8N1) using up most of the cpu?

Another old NeXT-Bug, a thousend times reported to NeXT, a thousend time  
nothing happened.... :-(

You can try to start the getty with 'nice' which makes it a bit less annoying,  
but the best would be, not to use disconnected ports.

-- 
------------------------------------------------------------------
Thomas Funke  ** E-mail: thf@zelator.in-berlin.de
NeXT-Developer * Unix-Consultant
------------------------------------------------------------------

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