From:	Schuster <Schuster AT eev DOT e-technik DOT uni-erlangen DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Interrupts Maximum Rate
Date:	Fri, 11 Apr 1997 14:54:47 -0700
Organization:	Lehrstuhl fuer Elektrische Energieversorgung
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Peter Berdeklis wrote:
> However, I think the problem addressed by the FAQ is not so much the
> maximum interrupt freq, but how high a freq before you notice a
> significant lag in your (non-trivial) program running in the foreground.
> This is not the case in your experiment I think, or am I wrong?
Yes.
Refering the maximum rate, you're right. But the let's say half of the
maximum 
rate enables pretty much time for calculating, also you can perform DMA
interrupts, 
so that the CPU can work in its cache, or the PCI-grafic card perhaps
does some
transfers,or whatever there is to be done in such a computer.

 
> Of course the rule of thumb offered by the FAQ may vary with program
> type.  A program that does a lot of waiting for user input could probably
> use your timings, but a CPU intensive prog might have noticable lag even
> below 10 kHz.

Ok, i don't want to initiate the holy war of
"Interrupts-cause-to-much-overhead" 
and "Polling-is-something-for-loosers". Just want to give some prooven
numbers.

I prefer the interrupt method, and my systems performs 12 khz wiht 12
channels 
to read, some drawing(with allegro :-), some calculation and I'm pleased
with 
it...


**********************************************
Michael Schuster
E-mail: Schuster AT eev DOT e-technik DOT uni-erlangen DOT de
Lehrstuhl fuer Elektrische Energieversorgung
http://www.eev.e-technik.uni-erlangen.de/

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